JAVA-12097: renamed algorithms-module to algorithms-modules

algorithms-modules/algorithms-genetic/.gitignore

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+/target/
+.settings/
+.classpath
+.project

algorithms-modules/algorithms-genetic/README.md

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+## Genetic Algorithms
+
+This module contains articles about genetic algorithms. 
+
+### Relevant articles:
+
+- [Introduction to Jenetics Library](https://www.baeldung.com/jenetics)
+- [Ant Colony Optimization with a Java Example](https://www.baeldung.com/java-ant-colony-optimization)
+- [Design a Genetic Algorithm in Java](https://www.baeldung.com/java-genetic-algorithm)
+- [The Traveling Salesman Problem in Java](https://www.baeldung.com/java-simulated-annealing-for-traveling-salesman)

algorithms-modules/algorithms-genetic/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>algorithms-genetic</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>algorithms-genetic</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>algorithms-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>${commons-math3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>commons-codec</groupId>
+            <artifactId>commons-codec</artifactId>
+            <version>${commons-codec.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok.version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.jenetics</groupId>
+            <artifactId>jenetics</artifactId>
+            <version>${io.jenetics.version}</version>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <commons-math3.version>3.6.1</commons-math3.version>
+        <io.jenetics.version>3.7.0</io.jenetics.version>
+        <commons-codec.version>1.11</commons-codec.version>
+    </properties>
+
+</project>

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/RunAlgorithm.java

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+package com.baeldung.algorithms;
+
+import java.util.Scanner;
+
+import com.baeldung.algorithms.ga.annealing.SimulatedAnnealing;
+import com.baeldung.algorithms.ga.ant_colony.AntColonyOptimization;
+import com.baeldung.algorithms.ga.binary.SimpleGeneticAlgorithm;
+
+public class RunAlgorithm {
+
+	public static void main(String[] args) throws InstantiationException, IllegalAccessException {
+		Scanner in = new Scanner(System.in);
+		System.out.println("Run algorithm:");
+		System.out.println("1 - Simulated Annealing");
+		System.out.println("2 - Simple Genetic Algorithm");
+		System.out.println("3 - Ant Colony");
+		int decision = in.nextInt();
+		switch (decision) {
+		case 1:
+			System.out.println(
+					"Optimized distance for travel: " + SimulatedAnnealing.simulateAnnealing(10, 10000, 0.9995));
+			break;
+		case 2:
+			SimpleGeneticAlgorithm ga = new SimpleGeneticAlgorithm();
+			ga.runAlgorithm(50, "1011000100000100010000100000100111001000000100000100000000001111");
+			break;
+		case 3:
+			AntColonyOptimization antColony = new AntColonyOptimization(21);
+			antColony.startAntOptimization();
+			break;
+		default:
+			System.out.println("Unknown option");
+			break;
+		}
+		in.close();
+	}
+
+}

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/annealing/City.java

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+package com.baeldung.algorithms.ga.annealing;
+
+import lombok.Data;
+
+@Data
+public class City {
+
+    private int x;
+    private int y;
+
+    public City() {
+        this.x = (int) (Math.random() * 500);
+        this.y = (int) (Math.random() * 500);
+    }
+
+    public double distanceToCity(City city) {
+        int x = Math.abs(getX() - city.getX());
+        int y = Math.abs(getY() - city.getY());
+        return Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2));
+    }
+
+}

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/annealing/SimulatedAnnealing.java

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+package com.baeldung.algorithms.ga.annealing;
+
+public class SimulatedAnnealing {
+
+    private static Travel travel = new Travel(10);
+
+    public static double simulateAnnealing(double startingTemperature, int numberOfIterations, double coolingRate) {
+        System.out.println("Starting SA with temperature: " + startingTemperature + ", # of iterations: " + numberOfIterations + " and colling rate: " + coolingRate);
+        double t = startingTemperature;
+        travel.generateInitialTravel();
+        double bestDistance = travel.getDistance();
+        System.out.println("Initial distance of travel: " + bestDistance);
+        Travel bestSolution = travel;
+        Travel currentSolution = bestSolution;
+
+        for (int i = 0; i < numberOfIterations; i++) {
+            if (t > 0.1) {
+                currentSolution.swapCities();
+                double currentDistance = currentSolution.getDistance();
+                if (currentDistance < bestDistance) {
+                    bestDistance = currentDistance;
+                } else if (Math.exp((bestDistance - currentDistance) / t) < Math.random()) {
+                    currentSolution.revertSwap();
+                }
+                t *= coolingRate;
+            } else {
+                continue;
+            }
+            if (i % 100 == 0) {
+                System.out.println("Iteration #" + i);
+            }
+        }
+        return bestDistance;
+    }
+
+}

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/annealing/Travel.java

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+package com.baeldung.algorithms.ga.annealing;
+
+import java.util.ArrayList;
+import java.util.Collections;
+
+import lombok.Data;
+
+@Data
+public class Travel {
+
+    private ArrayList<City> travel = new ArrayList<>();
+    private ArrayList<City> previousTravel = new ArrayList<>();
+
+    public Travel(int numberOfCities) {
+        for (int i = 0; i < numberOfCities; i++) {
+            travel.add(new City());
+        }
+    }
+
+    public void generateInitialTravel() {
+        if (travel.isEmpty()) {
+            new Travel(10);
+        }
+        Collections.shuffle(travel);
+    }
+
+    public void swapCities() {
+        int a = generateRandomIndex();
+        int b = generateRandomIndex();
+        previousTravel = new ArrayList<>(travel);
+        City x = travel.get(a);
+        City y = travel.get(b);
+        travel.set(a, y);
+        travel.set(b, x);
+    }
+
+    public void revertSwap() {
+        travel = previousTravel;
+    }
+
+    private int generateRandomIndex() {
+        return (int) (Math.random() * travel.size());
+    }
+
+    public City getCity(int index) {
+        return travel.get(index);
+    }
+
+    public int getDistance() {
+        int distance = 0;
+        for (int index = 0; index < travel.size(); index++) {
+            City starting = getCity(index);
+            City destination;
+            if (index + 1 < travel.size()) {
+                destination = getCity(index + 1);
+            } else {
+                destination = getCity(0);
+            }
+            distance += starting.distanceToCity(destination);
+        }
+        return distance;
+    }
+
+}

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/ant_colony/Ant.java

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+package com.baeldung.algorithms.ga.ant_colony;
+
+public class Ant {
+
+	protected int trailSize;
+	protected int trail[];
+	protected boolean visited[];
+
+	public Ant(int tourSize) {
+		this.trailSize = tourSize;
+		this.trail = new int[tourSize];
+		this.visited = new boolean[tourSize];
+	}
+
+	protected void visitCity(int currentIndex, int city) {
+		trail[currentIndex + 1] = city;
+		visited[city] = true;
+	}
+
+	protected boolean visited(int i) {
+		return visited[i];
+	}
+
+	protected double trailLength(double graph[][]) {
+		double length = graph[trail[trailSize - 1]][trail[0]];
+		for (int i = 0; i < trailSize - 1; i++) {
+			length += graph[trail[i]][trail[i + 1]];
+		}
+		return length;
+	}
+
+	protected void clear() {
+		for (int i = 0; i < trailSize; i++)
+			visited[i] = false;
+	}
+
+}

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/ant_colony/AntColonyOptimization.java

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+package com.baeldung.algorithms.ga.ant_colony;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.OptionalInt;
+import java.util.Random;
+import java.util.stream.IntStream;
+
+public class AntColonyOptimization {
+
+    private double c = 1.0;
+    private double alpha = 1;
+    private double beta = 5;
+    private double evaporation = 0.5;
+    private double Q = 500;
+    private double antFactor = 0.8;
+    private double randomFactor = 0.01;
+
+    private int maxIterations = 1000;
+
+    private int numberOfCities;
+    private int numberOfAnts;
+    private double graph[][];
+    private double trails[][];
+    private List<Ant> ants = new ArrayList<>();
+    private Random random = new Random();
+    private double probabilities[];
+
+    private int currentIndex;
+
+    private int[] bestTourOrder;
+    private double bestTourLength;
+
+    public AntColonyOptimization(int noOfCities) {
+        graph = generateRandomMatrix(noOfCities);
+        numberOfCities = graph.length;
+        numberOfAnts = (int) (numberOfCities * antFactor);
+
+        trails = new double[numberOfCities][numberOfCities];
+        probabilities = new double[numberOfCities];
+        IntStream.range(0, numberOfAnts)
+            .forEach(i -> ants.add(new Ant(numberOfCities)));
+    }
+
+    /**
+     * Generate initial solution
+     */
+    public double[][] generateRandomMatrix(int n) {
+        double[][] randomMatrix = new double[n][n];
+        IntStream.range(0, n)
+            .forEach(i -> IntStream.range(0, n)
+                .forEach(j -> randomMatrix[i][j] = Math.abs(random.nextInt(100) + 1)));
+        return randomMatrix;
+    }
+
+    /**
+     * Perform ant optimization
+     */
+    public void startAntOptimization() {
+        IntStream.rangeClosed(1, 3)
+            .forEach(i -> {
+                System.out.println("Attempt #" + i);
+                solve();
+            });
+    }
+
+    /**
+     * Use this method to run the main logic
+     */
+    public int[] solve() {
+        setupAnts();
+        clearTrails();
+        IntStream.range(0, maxIterations)
+            .forEach(i -> {
+                moveAnts();
+                updateTrails();
+                updateBest();
+            });
+        System.out.println("Best tour length: " + (bestTourLength - numberOfCities));
+        System.out.println("Best tour order: " + Arrays.toString(bestTourOrder));
+        return bestTourOrder.clone();
+    }
+
+    /**
+     * Prepare ants for the simulation
+     */
+    private void setupAnts() {
+        IntStream.range(0, numberOfAnts)
+            .forEach(i -> {
+                ants.forEach(ant -> {
+                    ant.clear();
+                    ant.visitCity(-1, random.nextInt(numberOfCities));
+                });
+            });
+        currentIndex = 0;
+    }
+
+    /**
+     * At each iteration, move ants
+     */
+    private void moveAnts() {
+        IntStream.range(currentIndex, numberOfCities - 1)
+            .forEach(i -> {
+                ants.forEach(ant -> ant.visitCity(currentIndex, selectNextCity(ant)));
+                currentIndex++;
+            });
+    }
+
+    /**
+     * Select next city for each ant
+     */
+    private int selectNextCity(Ant ant) {
+        int t = random.nextInt(numberOfCities - currentIndex);
+        if (random.nextDouble() < randomFactor) {
+            OptionalInt cityIndex = IntStream.range(0, numberOfCities)
+                .filter(i -> i == t && !ant.visited(i))
+                .findFirst();
+            if (cityIndex.isPresent()) {
+                return cityIndex.getAsInt();
+            }
+        }
+        calculateProbabilities(ant);
+        double r = random.nextDouble();
+        double total = 0;
+        for (int i = 0; i < numberOfCities; i++) {
+            total += probabilities[i];
+            if (total >= r) {
+                return i;
+            }
+        }
+
+        throw new RuntimeException("There are no other cities");
+    }
+
+    /**
+     * Calculate the next city picks probabilites
+     */
+    public void calculateProbabilities(Ant ant) {
+        int i = ant.trail[currentIndex];
+        double pheromone = 0.0;
+        for (int l = 0; l < numberOfCities; l++) {
+            if (!ant.visited(l)) {
+                pheromone += Math.pow(trails[i][l], alpha) * Math.pow(1.0 / graph[i][l], beta);
+            }
+        }
+        for (int j = 0; j < numberOfCities; j++) {
+            if (ant.visited(j)) {
+                probabilities[j] = 0.0;
+            } else {
+                double numerator = Math.pow(trails[i][j], alpha) * Math.pow(1.0 / graph[i][j], beta);
+                probabilities[j] = numerator / pheromone;
+            }
+        }
+    }
+
+    /**
+     * Update trails that ants used
+     */
+    private void updateTrails() {
+        for (int i = 0; i < numberOfCities; i++) {
+            for (int j = 0; j < numberOfCities; j++) {
+                trails[i][j] *= evaporation;
+            }
+        }
+        for (Ant a : ants) {
+            double contribution = Q / a.trailLength(graph);
+            for (int i = 0; i < numberOfCities - 1; i++) {
+                trails[a.trail[i]][a.trail[i + 1]] += contribution;
+            }
+            trails[a.trail[numberOfCities - 1]][a.trail[0]] += contribution;
+        }
+    }
+
+    /**
+     * Update the best solution
+     */
+    private void updateBest() {
+        if (bestTourOrder == null) {
+            bestTourOrder = ants.get(0).trail;
+            bestTourLength = ants.get(0)
+                .trailLength(graph);
+        }
+        for (Ant a : ants) {
+            if (a.trailLength(graph) < bestTourLength) {
+                bestTourLength = a.trailLength(graph);
+                bestTourOrder = a.trail.clone();
+            }
+        }
+    }
+
+    /**
+     * Clear trails after simulation
+     */
+    private void clearTrails() {
+        IntStream.range(0, numberOfCities)
+            .forEach(i -> {
+                IntStream.range(0, numberOfCities)
+                    .forEach(j -> trails[i][j] = c);
+            });
+    }
+
+}

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/binary/Individual.java

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+package com.baeldung.algorithms.ga.binary;
+
+import lombok.Data;
+
+@Data
+public class Individual {
+
+    protected int defaultGeneLength = 64;
+    private byte[] genes = new byte[defaultGeneLength];
+    private int fitness = 0;
+
+    public Individual() {
+        for (int i = 0; i < genes.length; i++) {
+            byte gene = (byte) Math.round(Math.random());
+            genes[i] = gene;
+        }
+    }
+
+    protected byte getSingleGene(int index) {
+        return genes[index];
+    }
+
+    protected void setSingleGene(int index, byte value) {
+        genes[index] = value;
+        fitness = 0;
+    }
+
+    public int getFitness() {
+        if (fitness == 0) {
+            fitness = SimpleGeneticAlgorithm.getFitness(this);
+        }
+        return fitness;
+    }
+
+    @Override
+    public String toString() {
+        String geneString = "";
+        for (int i = 0; i < genes.length; i++) {
+            geneString += getSingleGene(i);
+        }
+        return geneString;
+    }
+
+}

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/binary/Population.java

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+package com.baeldung.algorithms.ga.binary;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import lombok.Data;
+
+@Data
+public class Population {
+
+    private List<Individual> individuals;
+
+    public Population(int size, boolean createNew) {
+        individuals = new ArrayList<>();
+        if (createNew) {
+            createNewPopulation(size);
+        }
+    }
+
+    protected Individual getIndividual(int index) {
+        return individuals.get(index);
+    }
+
+    protected Individual getFittest() {
+        Individual fittest = individuals.get(0);
+        for (int i = 0; i < individuals.size(); i++) {
+            if (fittest.getFitness() <= getIndividual(i).getFitness()) {
+                fittest = getIndividual(i);
+            }
+        }
+        return fittest;
+    }
+
+    private void createNewPopulation(int size) {
+        for (int i = 0; i < size; i++) {
+            Individual newIndividual = new Individual();
+            individuals.add(i, newIndividual);
+        }
+    }
+}

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/binary/SimpleGeneticAlgorithm.java

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+package com.baeldung.algorithms.ga.binary;
+
+import lombok.Data;
+
+@Data
+public class SimpleGeneticAlgorithm {
+
+    private static final double uniformRate = 0.5;
+    private static final double mutationRate = 0.025;
+    private static final int tournamentSize = 5;
+    private static final boolean elitism = true;
+    private static byte[] solution = new byte[64];
+
+    public boolean runAlgorithm(int populationSize, String solution) {
+        if (solution.length() != SimpleGeneticAlgorithm.solution.length) {
+            throw new RuntimeException("The solution needs to have " + SimpleGeneticAlgorithm.solution.length + " bytes");
+        }
+        setSolution(solution);
+        Population myPop = new Population(populationSize, true);
+
+        int generationCount = 1;
+        while (myPop.getFittest().getFitness() < getMaxFitness()) {
+            System.out.println("Generation: " + generationCount + " Correct genes found: " + myPop.getFittest().getFitness());
+            myPop = evolvePopulation(myPop);
+            generationCount++;
+        }
+        System.out.println("Solution found!");
+        System.out.println("Generation: " + generationCount);
+        System.out.println("Genes: ");
+        System.out.println(myPop.getFittest());
+        return true;
+    }
+
+    public Population evolvePopulation(Population pop) {
+        int elitismOffset;
+        Population newPopulation = new Population(pop.getIndividuals().size(), false);
+
+        if (elitism) {
+            newPopulation.getIndividuals().add(0, pop.getFittest());
+            elitismOffset = 1;
+        } else {
+            elitismOffset = 0;
+        }
+
+        for (int i = elitismOffset; i < pop.getIndividuals().size(); i++) {
+            Individual indiv1 = tournamentSelection(pop);
+            Individual indiv2 = tournamentSelection(pop);
+            Individual newIndiv = crossover(indiv1, indiv2);
+            newPopulation.getIndividuals().add(i, newIndiv);
+        }
+
+        for (int i = elitismOffset; i < newPopulation.getIndividuals().size(); i++) {
+            mutate(newPopulation.getIndividual(i));
+        }
+
+        return newPopulation;
+    }
+
+    private Individual crossover(Individual indiv1, Individual indiv2) {
+        Individual newSol = new Individual();
+        for (int i = 0; i < newSol.getDefaultGeneLength(); i++) {
+            if (Math.random() <= uniformRate) {
+                newSol.setSingleGene(i, indiv1.getSingleGene(i));
+            } else {
+                newSol.setSingleGene(i, indiv2.getSingleGene(i));
+            }
+        }
+        return newSol;
+    }
+
+    private void mutate(Individual indiv) {
+        for (int i = 0; i < indiv.getDefaultGeneLength(); i++) {
+            if (Math.random() <= mutationRate) {
+                byte gene = (byte) Math.round(Math.random());
+                indiv.setSingleGene(i, gene);
+            }
+        }
+    }
+
+    private Individual tournamentSelection(Population pop) {
+        Population tournament = new Population(tournamentSize, false);
+        for (int i = 0; i < tournamentSize; i++) {
+            int randomId = (int) (Math.random() * pop.getIndividuals().size());
+            tournament.getIndividuals().add(i, pop.getIndividual(randomId));
+        }
+        Individual fittest = tournament.getFittest();
+        return fittest;
+    }
+
+    protected static int getFitness(Individual individual) {
+        int fitness = 0;
+        for (int i = 0; i < individual.getDefaultGeneLength() && i < solution.length; i++) {
+            if (individual.getSingleGene(i) == solution[i]) {
+                fitness++;
+            }
+        }
+        return fitness;
+    }
+
+    protected int getMaxFitness() {
+        int maxFitness = solution.length;
+        return maxFitness;
+    }
+
+    protected void setSolution(String newSolution) {
+        solution = new byte[newSolution.length()];
+        for (int i = 0; i < newSolution.length(); i++) {
+            String character = newSolution.substring(i, i + 1);
+            if (character.contains("0") || character.contains("1")) {
+                solution[i] = Byte.parseByte(character);
+            } else {
+                solution[i] = 0;
+            }
+        }
+    }
+
+}

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/jenetics/Knapsack.java

@@ -0,0 +1,47 @@
+package com.baeldung.algorithms.ga.jenetics;
+
+import static org.jenetics.engine.EvolutionResult.toBestPhenotype;
+import static org.jenetics.engine.limit.bySteadyFitness;
+
+import java.util.stream.Stream;
+
+import org.jenetics.BitChromosome;
+import org.jenetics.BitGene;
+import org.jenetics.Mutator;
+import org.jenetics.Phenotype;
+import org.jenetics.RouletteWheelSelector;
+import org.jenetics.SinglePointCrossover;
+import org.jenetics.TournamentSelector;
+import org.jenetics.engine.Engine;
+import org.jenetics.engine.EvolutionStatistics;
+
+//The main class.
+public class Knapsack {
+
+    public static void main(String[] args) {
+        int nItems = 15;
+        double ksSize = nItems * 100.0 / 3.0;
+
+        KnapsackFF ff = new KnapsackFF(Stream.generate(KnapsackItem::random)
+            .limit(nItems)
+            .toArray(KnapsackItem[]::new), ksSize);
+
+        Engine<BitGene, Double> engine = Engine.builder(ff, BitChromosome.of(nItems, 0.5))
+            .populationSize(500)
+            .survivorsSelector(new TournamentSelector<>(5))
+            .offspringSelector(new RouletteWheelSelector<>())
+            .alterers(new Mutator<>(0.115), new SinglePointCrossover<>(0.16))
+            .build();
+
+        EvolutionStatistics<Double, ?> statistics = EvolutionStatistics.ofNumber();
+
+        Phenotype<BitGene, Double> best = engine.stream()
+            .limit(bySteadyFitness(7))
+            .limit(100)
+            .peek(statistics)
+            .collect(toBestPhenotype());
+
+        System.out.println(statistics);
+        System.out.println(best);
+    }
+}

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/jenetics/KnapsackFF.java

@@ -0,0 +1,25 @@
+package com.baeldung.algorithms.ga.jenetics;
+
+import java.util.function.Function;
+
+import org.jenetics.BitChromosome;
+import org.jenetics.BitGene;
+import org.jenetics.Genotype;
+
+public class KnapsackFF implements Function<Genotype<BitGene>, Double> {
+    private KnapsackItem[] items;
+    private double size;
+
+    public KnapsackFF(KnapsackItem[] items, double size) {
+        this.items = items;
+        this.size = size;
+    }
+
+    @Override
+    public Double apply(Genotype<BitGene> gt) {
+        KnapsackItem sum = ((BitChromosome) gt.getChromosome()).ones()
+            .mapToObj(i -> items[i])
+            .collect(KnapsackItem.toSum());
+        return sum.size <= this.size ? sum.value : 0;
+    }
+}

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/jenetics/KnapsackItem.java

@@ -0,0 +1,34 @@
+package com.baeldung.algorithms.ga.jenetics;
+
+import java.util.Random;
+import java.util.stream.Collector;
+
+import org.jenetics.util.RandomRegistry;
+
+public class KnapsackItem {
+
+    public double size;
+    public double value;
+
+    public KnapsackItem(double size, double value) {
+        this.size = size;
+        this.value = value;
+    }
+
+    protected static KnapsackItem random() {
+        Random r = RandomRegistry.getRandom();
+        return new KnapsackItem(r.nextDouble() * 100, r.nextDouble() * 100);
+    }
+
+    protected static Collector<KnapsackItem, ?, KnapsackItem> toSum() {
+        return Collector.of(() -> new double[2], (a, b) -> {
+            a[0] += b.size;
+            a[1] += b.value;
+        } , (a, b) -> {
+            a[0] += b[0];
+            a[1] += b[1];
+            return a;
+        } , r -> new KnapsackItem(r[0], r[1]));
+    }
+
+}

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/jenetics/SimpleGeneticAlgorithm.java

@@ -0,0 +1,33 @@
+package com.baeldung.algorithms.ga.jenetics;
+
+import org.jenetics.BitChromosome;
+import org.jenetics.BitGene;
+import org.jenetics.Genotype;
+import org.jenetics.engine.Engine;
+import org.jenetics.engine.EvolutionResult;
+import org.jenetics.util.Factory;
+
+public class SimpleGeneticAlgorithm {
+
+    private static Integer eval(Genotype<BitGene> gt) {
+        return gt.getChromosome()
+            .as(BitChromosome.class)
+            .bitCount();
+    }
+
+    public static void main(String[] args) {
+        Factory<Genotype<BitGene>> gtf = Genotype.of(BitChromosome.of(10, 0.5));
+        System.out.println("Before the evolution:\n" + gtf);
+
+        Engine<BitGene, Integer> engine = Engine.builder(SimpleGeneticAlgorithm::eval, gtf)
+            .build();
+
+        Genotype<BitGene> result = engine.stream()
+            .limit(500)
+            .collect(EvolutionResult.toBestGenotype());
+
+        System.out.println("After the evolution:\n" + result);
+
+    }
+
+}

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/jenetics/SpringsteenProblem.java

@@ -0,0 +1,86 @@
+package com.baeldung.algorithms.ga.jenetics;
+
+import static java.util.Objects.requireNonNull;
+
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+import org.jenetics.BitGene;
+import org.jenetics.engine.Codec;
+import org.jenetics.engine.Engine;
+import org.jenetics.engine.EvolutionResult;
+import org.jenetics.engine.Problem;
+import org.jenetics.engine.codecs;
+import org.jenetics.util.ISeq;
+
+public class SpringsteenProblem implements Problem<ISeq<SpringsteenRecord>, BitGene, Double> {
+
+    private ISeq<SpringsteenRecord> records;
+    private double maxPricePerUniqueSong;
+
+    public SpringsteenProblem(ISeq<SpringsteenRecord> records, double maxPricePerUniqueSong) {
+        this.records = requireNonNull(records);
+        this.maxPricePerUniqueSong = maxPricePerUniqueSong;
+    }
+
+    @Override
+    public Function<ISeq<SpringsteenRecord>, Double> fitness() {
+        return SpringsteenRecords -> {
+            double cost = SpringsteenRecords.stream()
+                .mapToDouble(r -> r.price)
+                .sum();
+
+            int uniqueSongCount = SpringsteenRecords.stream()
+                .flatMap(r -> r.songs.stream())
+                .collect(Collectors.toSet())
+                .size();
+
+            double pricePerUniqueSong = cost / uniqueSongCount;
+
+            return pricePerUniqueSong <= maxPricePerUniqueSong ? uniqueSongCount : 0.0;
+        };
+    }
+
+    @Override
+    public Codec<ISeq<SpringsteenRecord>, BitGene> codec() {
+        return codecs.ofSubSet(records);
+    }
+
+    public static void main(String[] args) {
+        double maxPricePerUniqueSong = 2.5;
+
+        SpringsteenProblem springsteen = new SpringsteenProblem(
+            ISeq.of(new SpringsteenRecord("SpringsteenRecord1", 25, ISeq.of("Song1", "Song2", "Song3", "Song4", "Song5", "Song6")), new SpringsteenRecord("SpringsteenRecord2", 15, ISeq.of("Song2", "Song3", "Song4", "Song5", "Song6", "Song7")),
+                new SpringsteenRecord("SpringsteenRecord3", 35, ISeq.of("Song5", "Song6", "Song7", "Song8", "Song9", "Song10")), new SpringsteenRecord("SpringsteenRecord4", 17, ISeq.of("Song9", "Song10", "Song12", "Song4", "Song13", "Song14")),
+                new SpringsteenRecord("SpringsteenRecord5", 29, ISeq.of("Song1", "Song2", "Song13", "Song14", "Song15", "Song16")), new SpringsteenRecord("SpringsteenRecord6", 5, ISeq.of("Song18", "Song20", "Song30", "Song40"))),
+            maxPricePerUniqueSong);
+
+        Engine<BitGene, Double> engine = Engine.builder(springsteen)
+            .build();
+
+        ISeq<SpringsteenRecord> result = springsteen.codec()
+            .decoder()
+            .apply(engine.stream()
+                .limit(10)
+                .collect(EvolutionResult.toBestGenotype()));
+
+        double cost = result.stream()
+            .mapToDouble(r -> r.price)
+            .sum();
+
+        int uniqueSongCount = result.stream()
+            .flatMap(r -> r.songs.stream())
+            .collect(Collectors.toSet())
+            .size();
+
+        double pricePerUniqueSong = cost / uniqueSongCount;
+
+        System.out.println("Overall cost:  " + cost);
+        System.out.println("Unique songs:  " + uniqueSongCount);
+        System.out.println("Cost per song: " + pricePerUniqueSong);
+        System.out.println("Records:       " + result.map(r -> r.name)
+            .toString(", "));
+
+    }
+
+}

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/jenetics/SpringsteenRecord.java

@@ -0,0 +1,24 @@
+package com.baeldung.algorithms.ga.jenetics;
+
+import static java.util.Objects.requireNonNull;
+
+import org.jenetics.util.ISeq;
+
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@NoArgsConstructor
+public class SpringsteenRecord {
+
+    String name;
+    double price;
+    ISeq<String> songs;
+
+    public SpringsteenRecord(String name, double price, ISeq<String> songs) {
+        this.name = requireNonNull(name);
+        this.price = price;
+        this.songs = requireNonNull(songs);
+    }
+
+}

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/jenetics/SubsetSum.java

@@ -0,0 +1,66 @@
+package com.baeldung.algorithms.ga.jenetics;
+
+import static java.util.Objects.requireNonNull;
+
+import java.util.Random;
+import java.util.function.Function;
+
+import org.jenetics.EnumGene;
+import org.jenetics.Mutator;
+import org.jenetics.PartiallyMatchedCrossover;
+import org.jenetics.Phenotype;
+import org.jenetics.engine.Codec;
+import org.jenetics.engine.Engine;
+import org.jenetics.engine.EvolutionResult;
+import org.jenetics.engine.Problem;
+import org.jenetics.engine.codecs;
+import org.jenetics.engine.limit;
+import org.jenetics.util.ISeq;
+import org.jenetics.util.LCG64ShiftRandom;
+
+public class SubsetSum implements Problem<ISeq<Integer>, EnumGene<Integer>, Integer> {
+
+    private ISeq<Integer> basicSet;
+    private int size;
+
+    public SubsetSum(ISeq<Integer> basicSet, int size) {
+        this.basicSet = requireNonNull(basicSet);
+        this.size = size;
+    }
+
+    @Override
+    public Function<ISeq<Integer>, Integer> fitness() {
+        return subset -> Math.abs(subset.stream()
+            .mapToInt(Integer::intValue)
+            .sum());
+    }
+
+    @Override
+    public Codec<ISeq<Integer>, EnumGene<Integer>> codec() {
+        return codecs.ofSubSet(basicSet, size);
+    }
+
+    public static SubsetSum of(int n, int k, Random random) {
+        return new SubsetSum(random.doubles()
+            .limit(n)
+            .mapToObj(d -> (int) ((d - 0.5) * n))
+            .collect(ISeq.toISeq()), k);
+    }
+
+    public static void main(String[] args) {
+        SubsetSum problem = of(500, 15, new LCG64ShiftRandom(101010));
+
+        Engine<EnumGene<Integer>, Integer> engine = Engine.builder(problem)
+            .minimizing()
+            .maximalPhenotypeAge(5)
+            .alterers(new PartiallyMatchedCrossover<>(0.4), new Mutator<>(0.3))
+            .build();
+
+        Phenotype<EnumGene<Integer>, Integer> result = engine.stream()
+            .limit(limit.bySteadyFitness(55))
+            .collect(EvolutionResult.toBestPhenotype());
+
+        System.out.print(result);
+    }
+
+}

algorithms-modules/algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/jenetics/TravelingSalesman.java

@@ -0,0 +1,67 @@
+package com.baeldung.algorithms.ga.jenetics;
+
+import static java.lang.Math.PI;
+import static java.lang.Math.abs;
+import static java.lang.Math.sin;
+import static org.jenetics.engine.EvolutionResult.toBestPhenotype;
+import static org.jenetics.engine.limit.bySteadyFitness;
+
+import java.util.stream.IntStream;
+
+import org.jenetics.EnumGene;
+import org.jenetics.Optimize;
+import org.jenetics.PartiallyMatchedCrossover;
+import org.jenetics.Phenotype;
+import org.jenetics.SwapMutator;
+import org.jenetics.engine.Engine;
+import org.jenetics.engine.EvolutionStatistics;
+import org.jenetics.engine.codecs;
+
+public class TravelingSalesman {
+
+    private static final int STOPS = 50;
+    private static final double[][] ADJACENCE = matrix(STOPS);
+
+    private static double[][] matrix(int stops) {
+        final double radius = 100.0;
+        double[][] matrix = new double[stops][stops];
+
+        for (int i = 0; i < stops; ++i) {
+            for (int j = 0; j < stops; ++j) {
+                matrix[i][j] = chord(stops, abs(i - j), radius);
+            }
+        }
+        return matrix;
+    }
+
+    private static double chord(int stops, int i, double r) {
+        return 2.0 * r * abs(sin(PI * i / stops));
+    }
+
+    private static double dist(final int[] path) {
+        return IntStream.range(0, STOPS)
+            .mapToDouble(i -> ADJACENCE[path[i]][path[(i + 1) % STOPS]])
+            .sum();
+    }
+
+    public static void main(String[] args) {
+        final Engine<EnumGene<Integer>, Double> engine = Engine.builder(TravelingSalesman::dist, codecs.ofPermutation(STOPS))
+            .optimize(Optimize.MINIMUM)
+            .maximalPhenotypeAge(11)
+            .populationSize(500)
+            .alterers(new SwapMutator<>(0.2), new PartiallyMatchedCrossover<>(0.35))
+            .build();
+
+        final EvolutionStatistics<Double, ?> statistics = EvolutionStatistics.ofNumber();
+
+        final Phenotype<EnumGene<Integer>, Double> best = engine.stream()
+            .limit(bySteadyFitness(15))
+            .limit(250)
+            .peek(statistics)
+            .collect(toBestPhenotype());
+
+        System.out.println(statistics);
+        System.out.println(best);
+    }
+
+}

algorithms-modules/algorithms-genetic/src/main/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

algorithms-modules/algorithms-genetic/src/test/java/com/baeldung/algorithms/AntColonyOptimizationLongRunningUnitTest.java

@@ -0,0 +1,22 @@
+package com.baeldung.algorithms;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.baeldung.algorithms.ga.ant_colony.AntColonyOptimization;
+
+public class AntColonyOptimizationLongRunningUnitTest {
+
+    @Test
+    public void testGenerateRandomMatrix() {
+        AntColonyOptimization antTSP = new AntColonyOptimization(5);
+        Assert.assertNotNull(antTSP.generateRandomMatrix(5));
+    }
+
+    @Test
+    public void testStartAntOptimization() {
+        AntColonyOptimization antTSP = new AntColonyOptimization(5);
+        Assert.assertNotNull(antTSP.solve());
+    }
+
+}

algorithms-modules/algorithms-genetic/src/test/java/com/baeldung/algorithms/BinaryGeneticAlgorithmLongRunningUnitTest.java

@@ -0,0 +1,16 @@
+package com.baeldung.algorithms;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.baeldung.algorithms.ga.binary.SimpleGeneticAlgorithm;
+
+public class BinaryGeneticAlgorithmLongRunningUnitTest {
+
+    @Test
+    public void testGA() {
+        SimpleGeneticAlgorithm ga = new SimpleGeneticAlgorithm();
+        Assert.assertTrue(ga.runAlgorithm(50, "1011000100000100010000100000100111001000000100000100000000001111"));
+    }
+
+}

algorithms-modules/algorithms-genetic/src/test/java/com/baeldung/algorithms/SimulatedAnnealingLongRunningUnitTest.java

@@ -0,0 +1,15 @@
+package com.baeldung.algorithms;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.baeldung.algorithms.ga.annealing.SimulatedAnnealing;
+
+public class SimulatedAnnealingLongRunningUnitTest {
+
+    @Test
+    public void testSimulateAnnealing() {
+        Assert.assertTrue(SimulatedAnnealing.simulateAnnealing(10, 1000, 0.9) > 0);
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-1/README.md

@@ -0,0 +1,13 @@
+## Algorithms - Miscellaneous
+
+This module contains articles about algorithms. Some classes of algorithms, e.g., [sorting](/../algorithms-sorting) and
+[genetic algorithms](/../algorithms-genetic), have their own dedicated modules. 
+
+### Relevant articles:
+
+- [Validating Input With Finite Automata in Java](https://www.baeldung.com/java-finite-automata)
+- [Example of Hill Climbing Algorithm in Java](https://www.baeldung.com/java-hill-climbing-algorithm)
+- [Introduction to Minimax Algorithm with a Java Implementation](https://www.baeldung.com/java-minimax-algorithm)
+- [How to Calculate Levenshtein Distance in Java?](https://www.baeldung.com/java-levenshtein-distance)
+- [How to Find the Kth Largest Element in Java](https://www.baeldung.com/java-kth-largest-element)
+- More articles: [[next -->]](/algorithms-miscellaneous-2)

algorithms-modules/algorithms-miscellaneous-1/pom.xml

@@ -0,0 +1,72 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>algorithms-miscellaneous-1</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>algorithms-miscellaneous-1</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>algorithms-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>${commons-math3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>${guava.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>commons-codec</groupId>
+            <artifactId>commons-codec</artifactId>
+            <version>${commons-codec.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok.version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.github.dpaukov</groupId>
+            <artifactId>combinatoricslib3</artifactId>
+            <version>${combinatoricslib3.version}</version>
+        </dependency>
+    </dependencies>
+
+    <reporting>
+        <plugins>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>cobertura-maven-plugin</artifactId>
+                <version>${cobertura.plugin.version}</version>
+                <configuration>
+                    <instrumentation>
+                        <ignores>
+                            <ignore>com/baeldung/algorithms/dijkstra/*</ignore>
+                        </ignores>
+                        <excludes>
+                            <exclude>com/baeldung/algorithms/dijkstra/*</exclude>
+                        </excludes>
+                    </instrumentation>
+                </configuration>
+            </plugin>
+        </plugins>
+    </reporting>
+
+    <properties>
+        <commons-math3.version>3.6.1</commons-math3.version>
+        <commons-codec.version>1.11</commons-codec.version>
+        <combinatoricslib3.version>3.3.0</combinatoricslib3.version>
+        <cobertura.plugin.version>2.7</cobertura.plugin.version>
+    </properties>
+
+</project>

algorithms-modules/algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/automata/FiniteStateMachine.java

@@ -0,0 +1,20 @@
+package com.baeldung.algorithms.automata;
+
+/**
+ * Finite state machine.
+ */
+public interface FiniteStateMachine {
+
+    /**
+     * Follow a transition, switch the state of the machine.
+     * @param c Char.
+     * @return A new finite state machine with the new state.
+     */
+    FiniteStateMachine switchState(final CharSequence c);
+
+    /**
+     * Is the current state a final one?
+     * @return true or false.
+     */
+    boolean canStop();
+}

algorithms-modules/algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/automata/RtFiniteStateMachine.java

@@ -0,0 +1,30 @@
+package com.baeldung.algorithms.automata;
+
+/**
+ * Default implementation of a finite state machine.
+ * This class is immutable and thread-safe.
+ */
+public final class RtFiniteStateMachine implements FiniteStateMachine {
+
+    /**
+     * Current state.
+     */
+    private State current;
+
+    /**
+     * Ctor.
+     * @param initial Initial state of this machine.
+     */
+    public RtFiniteStateMachine(final State initial) {
+        this.current = initial;
+    }
+
+    public FiniteStateMachine switchState(final CharSequence c) {
+        return new RtFiniteStateMachine(this.current.transit(c));
+    }
+
+    public boolean canStop() {
+        return this.current.isFinal();
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/automata/RtState.java

@@ -0,0 +1,42 @@
+package com.baeldung.algorithms.automata;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * State in a finite state machine.
+ */
+public final class RtState implements State {
+
+    private List<Transition> transitions;
+    private boolean isFinal;
+
+    public RtState() {
+        this(false);
+    }
+    
+    public RtState(final boolean isFinal) {
+        this.transitions = new ArrayList<>();
+        this.isFinal = isFinal;
+    }
+
+    public State transit(final CharSequence c) {
+        return transitions
+          .stream()
+          .filter(t -> t.isPossible(c))
+          .map(Transition::state)
+          .findAny()
+          .orElseThrow(() -> new IllegalArgumentException("Input not accepted: " + c));
+    }
+
+    public boolean isFinal() {
+        return this.isFinal;
+    }
+
+    @Override
+    public State with(Transition tr) {
+        this.transitions.add(tr);
+        return this;
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/automata/RtTransition.java

@@ -0,0 +1,31 @@
+package com.baeldung.algorithms.automata;
+
+
+/**
+ * Transition in finite state machine.
+ */
+public final class RtTransition implements Transition {
+
+    private String rule;
+    private State next;
+    
+    /**
+     * Ctor.
+     * @param rule Rule that a character has to meet 
+     *  in order to get to the next state.  
+     * @param next Next state.
+     */
+    public RtTransition (String rule, State next) {
+        this.rule = rule;
+        this.next = next;
+    }
+    
+    public State state() {
+        return this.next;
+    }
+
+    public boolean isPossible(CharSequence c) {
+        return this.rule.equalsIgnoreCase(String.valueOf(c));
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/automata/State.java

@@ -0,0 +1,29 @@
+package com.baeldung.algorithms.automata;
+
+/**
+ * State. Part of a finite state machine.
+ */
+public interface State {
+
+    /**
+     * Add a Transition to this state.
+     * @param tr Given transition.
+     * @return Modified State.
+     */
+    State with(final Transition tr);
+
+    /**
+     * Follow one of the transitions, to get 
+     * to the next state.
+     * @param c Character.
+     * @return State.
+     * @throws IllegalStateException if the char is not accepted.
+     */
+    State transit(final CharSequence c);
+    
+    /**
+     * Can the automaton stop on this state?
+     * @return true or false
+     */
+    boolean isFinal();
+}

algorithms-modules/algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/automata/Transition.java

@@ -0,0 +1,20 @@
+package com.baeldung.algorithms.automata;
+
+/**
+ * Transition in a finite State machine.
+ */
+public interface Transition {
+
+    /**
+     * Is the transition possible with the given character?
+     * @param c char.
+     * @return true or false.
+     */
+    boolean isPossible(final CharSequence c);
+
+    /**
+     * The state to which this transition leads.
+     * @return State.
+     */
+    State state();
+}

algorithms-modules/algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/hillclimbing/HillClimbing.java

@@ -0,0 +1,189 @@
+package com.baeldung.algorithms.hillclimbing;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.Stack;
+
+public class HillClimbing {
+    public static void main(String[] args) {
+        HillClimbing hillClimbing = new HillClimbing();
+        String blockArr[] = { "B", "C", "D", "A" };
+        Stack<String> startState = hillClimbing.getStackWithValues(blockArr);
+        String goalBlockArr[] = { "A", "B", "C", "D" };
+        Stack<String> goalState = hillClimbing.getStackWithValues(goalBlockArr);
+        try {
+            List<State> solutionSequence = hillClimbing.getRouteWithHillClimbing(startState, goalState);
+            solutionSequence.forEach(HillClimbing::printEachStep);
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    private static void printEachStep(State state) {
+        List<Stack<String>> stackList = state.getState();
+        System.out.println("----------------");
+        stackList.forEach(stack -> {
+            while (!stack.isEmpty()) {
+                System.out.println(stack.pop());
+            }
+            System.out.println(" ");
+        });
+    }
+
+    private Stack<String> getStackWithValues(String[] blocks) {
+        Stack<String> stack = new Stack<>();
+        for (String block : blocks)
+            stack.push(block);
+        return stack;
+    }
+
+    /**
+     * This method prepares path from init state to goal state
+     */
+    public List<State> getRouteWithHillClimbing(Stack<String> initStateStack, Stack<String> goalStateStack) throws Exception {
+        List<Stack<String>> initStateStackList = new ArrayList<>();
+        initStateStackList.add(initStateStack);
+        int initStateHeuristics = getHeuristicsValue(initStateStackList, goalStateStack);
+        State initState = new State(initStateStackList, initStateHeuristics);
+
+        List<State> resultPath = new ArrayList<>();
+        resultPath.add(new State(initState));
+
+        State currentState = initState;
+        boolean noStateFound = false;
+        while (!currentState.getState()
+            .get(0)
+            .equals(goalStateStack) || noStateFound) {
+            noStateFound = true;
+            State nextState = findNextState(currentState, goalStateStack);
+            if (nextState != null) {
+                noStateFound = false;
+                currentState = nextState;
+                resultPath.add(new State(nextState));
+            }
+        }
+
+        return resultPath;
+    }
+
+    /**
+     * This method finds new state from current state based on goal and
+     * heuristics
+     */
+    public State findNextState(State currentState, Stack<String> goalStateStack) {
+        List<Stack<String>> listOfStacks = currentState.getState();
+        int currentStateHeuristics = currentState.getHeuristics();
+
+        return listOfStacks.stream()
+            .map(stack -> {
+                return applyOperationsOnState(listOfStacks, stack, currentStateHeuristics, goalStateStack);
+            })
+            .filter(Objects::nonNull)
+            .findFirst()
+          .orElse(null);
+    }
+
+    /**
+     * This method applies operations on the current state to get a new state
+     */
+    public State applyOperationsOnState(List<Stack<String>> listOfStacks, Stack<String> stack, int currentStateHeuristics, Stack<String> goalStateStack) {
+        State tempState;
+        List<Stack<String>> tempStackList = new ArrayList<>(listOfStacks);
+        String block = stack.pop();
+        if (stack.size() == 0)
+            tempStackList.remove(stack);
+        tempState = pushElementToNewStack(tempStackList, block, currentStateHeuristics, goalStateStack);
+        if (tempState == null) {
+            tempState = pushElementToExistingStacks(stack, tempStackList, block, currentStateHeuristics, goalStateStack);
+        }
+        if (tempState == null)
+            stack.push(block);
+        return tempState;
+    }
+    
+    /**
+     * Operation to be applied on a state in order to find new states. This
+     * operation pushes an element into a new stack
+     */
+    private State pushElementToNewStack(List<Stack<String>> currentStackList, String block, int currentStateHeuristics, Stack<String> goalStateStack) {
+        State newState = null;
+        Stack<String> newStack = new Stack<>();
+        newStack.push(block);
+
+        currentStackList.add(newStack);
+        int newStateHeuristics = getHeuristicsValue(currentStackList, goalStateStack);
+        if (newStateHeuristics > currentStateHeuristics) {
+            newState = new State(currentStackList, newStateHeuristics);
+        } else {
+            currentStackList.remove(newStack);
+        }
+        return newState;
+    }
+
+    /**
+     * Operation to be applied on a state in order to find new states. This
+     * operation pushes an element into one of the other stacks to explore new
+     * states
+     */
+    private State pushElementToExistingStacks(Stack currentStack, List<Stack<String>> currentStackList, String block, int currentStateHeuristics, Stack<String> goalStateStack) {
+
+        Optional<State> newState = currentStackList.stream()
+            .filter(stack -> stack != currentStack)
+            .map(stack -> {
+                return pushElementToStack(stack, block, currentStackList, currentStateHeuristics, goalStateStack);
+            })
+            .filter(Objects::nonNull)
+            .findFirst();
+
+        return newState.orElse(null);
+    }
+    
+    /**
+     * This method pushes a block to the stack and returns new state if its closer to goal
+     */
+    private State pushElementToStack(Stack stack, String block, List<Stack<String>> currentStackList, int currentStateHeuristics, Stack<String> goalStateStack) {
+        stack.push(block);
+        int newStateHeuristics = getHeuristicsValue(currentStackList, goalStateStack);
+        if (newStateHeuristics > currentStateHeuristics) {
+            return new State(currentStackList, newStateHeuristics);
+        }
+        stack.pop();
+        return null;
+    }
+
+    /**
+     * This method returns heuristics value for given state with respect to goal
+     * state
+     */
+    public int getHeuristicsValue(List<Stack<String>> currentState, Stack<String> goalStateStack) {
+        Integer heuristicValue;
+        heuristicValue = currentState.stream()
+            .mapToInt(stack -> {
+                return getHeuristicsValueForStack(stack, currentState, goalStateStack);
+            })
+            .sum();
+        return heuristicValue;
+    }
+    
+    /**
+     * This method returns heuristics value for a particular stack
+     */
+    public int getHeuristicsValueForStack(Stack<String> stack, List<Stack<String>> currentState, Stack<String> goalStateStack) {
+        int stackHeuristics = 0;
+        boolean isPositioneCorrect = true;
+        int goalStartIndex = 0;
+        for (String currentBlock : stack) {
+            if (isPositioneCorrect && currentBlock.equals(goalStateStack.get(goalStartIndex))) {
+                stackHeuristics += goalStartIndex;
+            } else {
+                stackHeuristics -= goalStartIndex;
+                isPositioneCorrect = false;
+            }
+            goalStartIndex++;
+        }
+        return stackHeuristics;
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/hillclimbing/State.java

@@ -0,0 +1,43 @@
+package com.baeldung.algorithms.hillclimbing;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Stack;
+
+public class State {
+    private List<Stack<String>> state;
+    private int heuristics;
+
+    public State(List<Stack<String>> state) {
+        this.state = state;
+    }
+
+    State(List<Stack<String>> state, int heuristics) {
+        this.state = state;
+        this.heuristics = heuristics;
+    }
+
+    State(State state) {
+        if (state != null) {
+            this.state = new ArrayList<>();
+            for (Stack s : state.getState()) {
+                Stack s1;
+                s1 = (Stack) s.clone();
+                this.state.add(s1);
+            }
+            this.heuristics = state.getHeuristics();
+        }
+    }
+
+    public List<Stack<String>> getState() {
+        return state;
+    }
+
+    public int getHeuristics() {
+        return heuristics;
+    }
+
+    public void setHeuristics(int heuristics) {
+        this.heuristics = heuristics;
+    }
+}

algorithms-modules/algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/kthlargest/FindKthLargest.java

@@ -0,0 +1,111 @@
+package com.baeldung.algorithms.kthlargest;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.stream.IntStream;
+
+public class FindKthLargest {
+
+    public int findKthLargestBySorting(Integer[] arr, int k) {
+        Arrays.sort(arr);
+        int targetIndex = arr.length - k;
+        return arr[targetIndex];
+    }
+
+    public int findKthLargestBySortingDesc(Integer[] arr, int k) {
+        Arrays.sort(arr, Collections.reverseOrder());
+        return arr[k - 1];
+    }
+
+    public int findKthElementByQuickSelect(Integer[] arr, int left, int right, int k) {
+        if (k >= 0 && k <= right - left + 1) {
+            int pos = partition(arr, left, right);
+            if (pos - left == k) {
+                return arr[pos];
+            }
+            if (pos - left > k) {
+                return findKthElementByQuickSelect(arr, left, pos - 1, k);
+            }
+            return findKthElementByQuickSelect(arr, pos + 1, right, k - pos + left - 1);
+        }
+        return 0;
+    }
+
+    public int findKthElementByQuickSelectWithIterativePartition(Integer[] arr, int left, int right, int k) {
+        if (k >= 0 && k <= right - left + 1) {
+            int pos = partitionIterative(arr, left, right);
+            if (pos - left == k) {
+                return arr[pos];
+            }
+            if (pos - left > k) {
+                return findKthElementByQuickSelectWithIterativePartition(arr, left, pos - 1, k);
+            }
+            return findKthElementByQuickSelectWithIterativePartition(arr, pos + 1, right, k - pos + left - 1);
+        }
+        return 0;
+    }
+
+    private int partition(Integer[] arr, int left, int right) {
+        int pivot = arr[right];
+        Integer[] leftArr;
+        Integer[] rightArr;
+
+        leftArr = IntStream.range(left, right)
+            .filter(i -> arr[i] < pivot)
+            .map(i -> arr[i])
+            .boxed()
+            .toArray(Integer[]::new);
+
+        rightArr = IntStream.range(left, right)
+            .filter(i -> arr[i] > pivot)
+            .map(i -> arr[i])
+            .boxed()
+            .toArray(Integer[]::new);
+
+        int leftArraySize = leftArr.length;
+        System.arraycopy(leftArr, 0, arr, left, leftArraySize);
+        arr[leftArraySize + left] = pivot;
+        System.arraycopy(rightArr, 0, arr, left + leftArraySize + 1, rightArr.length);
+
+        return left + leftArraySize;
+    }
+
+    private int partitionIterative(Integer[] arr, int left, int right) {
+        int pivot = arr[right], i = left;
+        for (int j = left; j <= right - 1; j++) {
+            if (arr[j] <= pivot) {
+                swap(arr, i, j);
+                i++;
+            }
+        }
+        swap(arr, i, right);
+        return i;
+    }
+
+    public int findKthElementByRandomizedQuickSelect(Integer[] arr, int left, int right, int k) {
+        if (k >= 0 && k <= right - left + 1) {
+            int pos = randomPartition(arr, left, right);
+            if (pos - left == k) {
+                return arr[pos];
+            }
+            if (pos - left > k) {
+                return findKthElementByRandomizedQuickSelect(arr, left, pos - 1, k);
+            }
+            return findKthElementByRandomizedQuickSelect(arr, pos + 1, right, k - pos + left - 1);
+        }
+        return 0;
+    }
+
+    private int randomPartition(Integer arr[], int left, int right) {
+        int n = right - left + 1;
+        int pivot = (int) (Math.random() * n);
+        swap(arr, left + pivot, right);
+        return partition(arr, left, right);
+    }
+
+    private void swap(Integer[] arr, int n1, int n2) {
+        int temp = arr[n2];
+        arr[n2] = arr[n1];
+        arr[n1] = temp;
+    }
+}

algorithms-modules/algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/minimax/GameOfBones.java

@@ -0,0 +1,14 @@
+package com.baeldung.algorithms.minimax;
+
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+class GameOfBones {
+    static List<Integer> getPossibleStates(int noOfBonesInHeap) {
+        return IntStream.rangeClosed(1, 3).boxed()
+          .map(i -> noOfBonesInHeap - i)
+          .filter(newHeapCount -> newHeapCount >= 0)
+          .collect(Collectors.toList());
+    }
+}

algorithms-modules/algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/minimax/MiniMax.java

@@ -0,0 +1,60 @@
+package com.baeldung.algorithms.minimax;
+
+import java.util.Comparator;
+import java.util.List;
+import java.util.NoSuchElementException;
+
+public class MiniMax {
+    private Tree tree;
+
+    public Tree getTree() {
+        return tree;
+    }
+
+    public void constructTree(int noOfBones) {
+        tree = new Tree();
+        Node root = new Node(noOfBones, true);
+        tree.setRoot(root);
+        constructTree(root);
+    }
+
+    private void constructTree(Node parentNode) {
+        List<Integer> listofPossibleHeaps = GameOfBones.getPossibleStates(parentNode.getNoOfBones());
+        boolean isChildMaxPlayer = !parentNode.isMaxPlayer();
+        listofPossibleHeaps.forEach(n -> {
+            Node newNode = new Node(n, isChildMaxPlayer);
+            parentNode.addChild(newNode);
+            if (newNode.getNoOfBones() > 0) {
+                constructTree(newNode);
+            }
+        });
+    }
+
+    public boolean checkWin() {
+        Node root = tree.getRoot();
+        checkWin(root);
+        return root.getScore() == 1;
+    }
+
+    private void checkWin(Node node) {
+        List<Node> children = node.getChildren();
+        boolean isMaxPlayer = node.isMaxPlayer();
+        children.forEach(child -> {
+            if (child.getNoOfBones() == 0) {
+                child.setScore(isMaxPlayer ? 1 : -1);
+            } else {
+                checkWin(child);
+            }
+        });
+        Node bestChild = findBestChild(isMaxPlayer, children);
+        node.setScore(bestChild.getScore());
+    }
+
+    private Node findBestChild(boolean isMaxPlayer, List<Node> children) {
+        Comparator<Node> byScoreComparator = Comparator.comparing(Node::getScore);
+
+        return children.stream()
+          .max(isMaxPlayer ? byScoreComparator : byScoreComparator.reversed())
+          .orElseThrow(NoSuchElementException::new);
+    }
+}

algorithms-modules/algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/minimax/Node.java

@@ -0,0 +1,42 @@
+package com.baeldung.algorithms.minimax;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Node {
+    private int noOfBones;
+    private boolean isMaxPlayer;
+    private int score;
+    private List<Node> children;
+
+    public Node(int noOfBones, boolean isMaxPlayer) {
+        this.noOfBones = noOfBones;
+        this.isMaxPlayer = isMaxPlayer;
+        children = new ArrayList<>();
+    }
+
+    int getNoOfBones() {
+        return noOfBones;
+    }
+
+    boolean isMaxPlayer() {
+        return isMaxPlayer;
+    }
+
+    int getScore() {
+        return score;
+    }
+
+    void setScore(int score) {
+        this.score = score;
+    }
+
+    List<Node> getChildren() {
+        return children;
+    }
+
+    void addChild(Node newNode) {
+        children.add(newNode);
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/minimax/Tree.java

@@ -0,0 +1,16 @@
+package com.baeldung.algorithms.minimax;
+
+public class Tree {
+    private Node root;
+
+    Tree() {
+    }
+
+    Node getRoot() {
+        return root;
+    }
+
+    void setRoot(Node root) {
+        this.root = root;
+    }
+}

algorithms-modules/algorithms-miscellaneous-1/src/main/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

algorithms-modules/algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/HillClimbingAlgorithmUnitTest.java

@@ -0,0 +1,58 @@
+package com.baeldung.algorithms;
+
+import com.baeldung.algorithms.hillclimbing.HillClimbing;
+import com.baeldung.algorithms.hillclimbing.State;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Stack;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+public class HillClimbingAlgorithmUnitTest {
+    private Stack<String> initStack;
+    private Stack<String> goalStack;
+
+    @Before
+    public void initStacks() {
+        String blockArr[] = { "B", "C", "D", "A" };
+        String goalBlockArr[] = { "A", "B", "C", "D" };
+        initStack = new Stack<>();
+        for (String block : blockArr)
+            initStack.push(block);
+        goalStack = new Stack<>();
+        for (String block : goalBlockArr)
+            goalStack.push(block);
+    }
+
+    @Test
+    public void givenInitAndGoalState_whenGetPathWithHillClimbing_thenPathFound() {
+        HillClimbing hillClimbing = new HillClimbing();
+
+        List<State> path;
+        try {
+            path = hillClimbing.getRouteWithHillClimbing(initStack, goalStack);
+            assertNotNull(path);
+            assertEquals(path.get(path.size() - 1)
+                .getState()
+                .get(0), goalStack);
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    @Test
+    public void givenCurrentState_whenFindNextState_thenBetterHeuristics() {
+        HillClimbing hillClimbing = new HillClimbing();
+        List<Stack<String>> initList = new ArrayList<>();
+        initList.add(initStack);
+        State currentState = new State(initList);
+        currentState.setHeuristics(hillClimbing.getHeuristicsValue(initList, goalStack));
+        State nextState = hillClimbing.findNextState(currentState, goalStack);
+        assertTrue(nextState.getHeuristics() > currentState.getHeuristics());
+    }
+}

algorithms-modules/algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/RtFiniteStateMachineLongRunningUnitTest.java

@@ -0,0 +1,73 @@
+package com.baeldung.algorithms;
+
+import com.baeldung.algorithms.automata.*;
+import org.junit.Test;
+
+import static org.junit.Assert.assertTrue;
+
+public final class RtFiniteStateMachineLongRunningUnitTest {
+
+    @Test
+    public void acceptsSimplePair() {
+        String json = "{\"key\":\"value\"}";
+        FiniteStateMachine machine = this.buildJsonStateMachine();
+        for (int i = 0; i < json.length(); i++) {
+            machine = machine.switchState(String.valueOf(json.charAt(i)));
+        }
+        assertTrue(machine.canStop());
+    }
+
+    @Test
+    public void acceptsMorePairs() {
+        String json = "{\"key1\":\"value1\",\"key2\":\"value2\"}";
+        FiniteStateMachine machine = this.buildJsonStateMachine();
+        for (int i = 0; i < json.length(); i++) {
+            machine = machine.switchState(String.valueOf(json.charAt(i)));
+        }
+        assertTrue(machine.canStop());
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void missingColon() {
+        String json = "{\"key\"\"value\"}";
+        FiniteStateMachine machine = this.buildJsonStateMachine();
+        for (int i = 0; i < json.length(); i++) {
+            machine = machine.switchState(String.valueOf(json.charAt(i)));
+        }
+    }
+
+    /**
+     * Builds a finite state machine to validate a simple
+     * Json object.
+     * @return
+     */
+    private FiniteStateMachine buildJsonStateMachine() {
+        State first = new RtState();
+        State second = new RtState();
+        State third = new RtState();
+        State fourth = new RtState();
+        State fifth = new RtState();
+        State sixth = new RtState();
+        State seventh = new RtState();
+        State eighth = new RtState(true);
+
+        first.with(new RtTransition("{", second));
+        second.with(new RtTransition("\"", third));
+        //Add transitions with chars 0-9 and a-z
+        for (int i = 0; i < 26; i++) {
+            if (i < 10) {
+                third = third.with(new RtTransition(String.valueOf(i), third));
+                sixth = sixth.with(new RtTransition(String.valueOf(i), sixth));
+            }
+            third = third.with(new RtTransition(String.valueOf((char) ('a' + i)), third));
+            sixth = sixth.with(new RtTransition(String.valueOf((char) ('a' + i)), sixth));
+        }
+        third.with(new RtTransition("\"", fourth));
+        fourth.with(new RtTransition(":", fifth));
+        fifth.with(new RtTransition("\"", sixth));
+        sixth.with(new RtTransition("\"", seventh));
+        seventh.with(new RtTransition(",", second));
+        seventh.with(new RtTransition("}", eighth));
+        return new RtFiniteStateMachine(first);
+    }
+}

algorithms-modules/algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/kthlargest/FindKthLargestUnitTest.java

@@ -0,0 +1,57 @@
+package com.baeldung.algorithms.kthlargest;
+
+import static org.assertj.core.api.Assertions.*;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class FindKthLargestUnitTest {
+
+    private FindKthLargest findKthLargest;
+    private Integer[] arr = { 3, 7, 1, 2, 8, 10, 4, 5, 6, 9 };
+
+    @Before
+    public void setup() {
+        findKthLargest = new FindKthLargest();
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthLargestBySorting_thenGetResult() {
+        int k = 3;
+        assertThat(findKthLargest.findKthLargestBySorting(arr, k)).isEqualTo(8);
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthLargestBySortingDesc_thenGetResult() {
+        int k = 3;
+        assertThat(findKthLargest.findKthLargestBySortingDesc(arr, k)).isEqualTo(8);
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthLargestByQuickSelect_thenGetResult() {
+        int k = 3;
+        int kthLargest = arr.length - k;
+        assertThat(findKthLargest.findKthElementByQuickSelect(arr, 0, arr.length - 1, kthLargest)).isEqualTo(8);
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthElementByQuickSelectIterative_thenGetResult() {
+        int k = 3;
+        int kthLargest = arr.length - k;
+        assertThat(findKthLargest.findKthElementByQuickSelectWithIterativePartition(arr, 0, arr.length - 1, kthLargest)).isEqualTo(8);
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthSmallestByQuickSelect_thenGetResult() {
+        int k = 3;
+        assertThat(findKthLargest.findKthElementByQuickSelect(arr, 0, arr.length - 1, k - 1)).isEqualTo(3);
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthLargestByRandomizedQuickSelect_thenGetResult() {
+        int k = 3;
+        int kthLargest = arr.length - k;
+        assertThat(findKthLargest.findKthElementByRandomizedQuickSelect(arr, 0, arr.length - 1, kthLargest)).isEqualTo(8);
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/minimax/MinimaxUnitTest.java

@@ -0,0 +1,36 @@
+package com.baeldung.algorithms.minimax;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+import com.baeldung.algorithms.minimax.MiniMax;
+import com.baeldung.algorithms.minimax.Tree;
+
+public class MinimaxUnitTest {
+    private Tree gameTree;
+    private MiniMax miniMax;
+
+    @Before
+    public void initMiniMaxUtility() {
+        miniMax = new MiniMax();
+    }
+
+    @Test
+    public void givenMiniMax_whenConstructTree_thenNotNullTree() {
+        assertNull(gameTree);
+        miniMax.constructTree(6);
+        gameTree = miniMax.getTree();
+        assertNotNull(gameTree);
+    }
+
+    @Test
+    public void givenMiniMax_whenCheckWin_thenComputeOptimal() {
+        miniMax.constructTree(6);
+        boolean result = miniMax.checkWin();
+        assertTrue(result);
+        miniMax.constructTree(8);
+        result = miniMax.checkWin();
+        assertFalse(result);
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/README.md

@@ -0,0 +1,17 @@
+## Algorithms - Miscellaneous
+
+This module contains articles about algorithms. Some classes of algorithms, e.g., [sorting](/../algorithms-sorting) and
+[genetic algorithms](/../algorithms-genetic), have their own dedicated modules. 
+
+### Relevant articles:
+
+- [Dijkstra Shortest Path Algorithm in Java](https://www.baeldung.com/java-dijkstra)
+- [Introduction to Cobertura](https://www.baeldung.com/cobertura)
+- [Test a Linked List for Cyclicity](https://www.baeldung.com/java-linked-list-cyclicity)
+- [Introduction to JGraphT](https://www.baeldung.com/jgrapht)
+- [A Maze Solver in Java](https://www.baeldung.com/java-solve-maze)
+- [Create a Sudoku Solver in Java](https://www.baeldung.com/java-sudoku)
+- [Displaying Money Amounts in Words](https://www.baeldung.com/java-money-into-words)
+- [A Collaborative Filtering Recommendation System in Java](https://www.baeldung.com/java-collaborative-filtering-recommendations)
+- [Implementing A* Pathfinding in Java](https://www.baeldung.com/java-a-star-pathfinding)
+- More articles: [[<-- prev]](/algorithms-miscellaneous-1) [[next -->]](/algorithms-miscellaneous-3)

algorithms-modules/algorithms-miscellaneous-2/pom.xml

@@ -0,0 +1,79 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>algorithms-miscellaneous-2</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>algorithms-miscellaneous-2</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>algorithms-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>${commons-math3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>commons-codec</groupId>
+            <artifactId>commons-codec</artifactId>
+            <version>${commons-codec.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok.version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.jgrapht</groupId>
+            <artifactId>jgrapht-core</artifactId>
+            <version>${org.jgrapht.core.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.jgrapht</groupId>
+            <artifactId>jgrapht-ext</artifactId>
+            <version>${org.jgrapht.ext.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>pl.allegro.finance</groupId>
+            <artifactId>tradukisto</artifactId>
+            <version>${tradukisto.version}</version>
+        </dependency>
+    </dependencies>
+
+    <reporting>
+        <plugins>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>cobertura-maven-plugin</artifactId>
+                <version>${cobertura-maven-plugin.version}</version>
+                <configuration>
+                    <instrumentation>
+                        <ignores>
+                            <ignore>com/baeldung/algorithms/dijkstra/*</ignore>
+                        </ignores>
+                        <excludes>
+                            <exclude>com/baeldung/algorithms/dijkstra/*</exclude>
+                        </excludes>
+                    </instrumentation>
+                </configuration>
+            </plugin>
+        </plugins>
+    </reporting>
+
+    <properties>
+        <commons-math3.version>3.6.1</commons-math3.version>
+        <tradukisto.version>1.0.1</tradukisto.version>
+        <org.jgrapht.core.version>1.0.1</org.jgrapht.core.version>
+        <org.jgrapht.ext.version>1.0.1</org.jgrapht.ext.version>
+        <commons-codec.version>1.11</commons-codec.version>
+        <cobertura-maven-plugin.version>2.7</cobertura-maven-plugin.version>
+    </properties>
+
+</project>

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/RunAlgorithm.java

@@ -0,0 +1,28 @@
+package com.baeldung.algorithms;
+
+import java.util.Scanner;
+
+import com.baeldung.algorithms.slope_one.SlopeOne;
+
+public class RunAlgorithm {
+
+	public static void main(String[] args) throws InstantiationException, IllegalAccessException {
+		Scanner in = new Scanner(System.in);
+		System.out.println("1 - Slope One");
+		System.out.println("2 - Dijkstra");
+		int decision = in.nextInt();
+		switch (decision) {
+		case 1:
+			SlopeOne.slopeOne(3);
+			break;
+		case 2:
+			System.out.println("Please run the DijkstraAlgorithmLongRunningUnitTest.");
+			break;
+		default:
+			System.out.println("Unknown option");
+			break;
+		}
+		in.close();
+	}
+
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/editdistance/EditDistanceBase.java

@@ -0,0 +1,15 @@
+package com.baeldung.algorithms.editdistance;
+
+import java.util.Arrays;
+
+public class EditDistanceBase {
+
+    static int costOfSubstitution(char a, char b) {
+        return a == b ? 0 : 1;
+    }
+
+    static int min(int... numbers) {
+        return Arrays.stream(numbers)
+          .min().orElse(Integer.MAX_VALUE);
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/editdistance/EditDistanceDynamicProgramming.java

@@ -0,0 +1,26 @@
+package com.baeldung.algorithms.editdistance;
+
+public class EditDistanceDynamicProgramming extends EditDistanceBase {
+
+    static int calculate(String x, String y) {
+        int[][] dp = new int[x.length() + 1][y.length() + 1];
+
+        for (int i = 0; i <= x.length(); i++) {
+            for (int j = 0; j <= y.length(); j++) {
+                if (i == 0)
+                    dp[i][j] = j;
+
+                else if (j == 0)
+                    dp[i][j] = i;
+
+                else {
+                    dp[i][j] = min(dp[i - 1][j - 1]
+                        + costOfSubstitution(x.charAt(i - 1), y.charAt(j - 1)),
+                      dp[i - 1][j] + 1, dp[i][j - 1] + 1);
+                }
+            }
+        }
+
+        return dp[x.length()][y.length()];
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/editdistance/EditDistanceRecursive.java

@@ -0,0 +1,21 @@
+package com.baeldung.algorithms.editdistance;
+
+public class EditDistanceRecursive extends EditDistanceBase {
+
+    static int calculate(String x, String y) {
+
+        if (x.isEmpty()) {
+            return y.length();
+        }
+
+        if (y.isEmpty()) {
+            return x.length();
+        }
+
+        int substitution = calculate(x.substring(1), y.substring(1)) + costOfSubstitution(x.charAt(0), y.charAt(0));
+        int insertion = calculate(x, y.substring(1)) + 1;
+        int deletion = calculate(x.substring(1), y) + 1;
+
+        return min(substitution, insertion, deletion);
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/ga/dijkstra/Dijkstra.java

@@ -0,0 +1,57 @@
+package com.baeldung.algorithms.ga.dijkstra;
+
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.Map.Entry;
+import java.util.Set;
+
+public class Dijkstra {
+
+    public static Graph calculateShortestPathFromSource(Graph graph, Node source) {
+
+        source.setDistance(0);
+
+        Set<Node> settledNodes = new HashSet<>();
+        Set<Node> unsettledNodes = new HashSet<>();
+        unsettledNodes.add(source);
+
+        while (unsettledNodes.size() != 0) {
+            Node currentNode = getLowestDistanceNode(unsettledNodes);
+            unsettledNodes.remove(currentNode);
+            for (Entry<Node, Integer> adjacencyPair : currentNode.getAdjacentNodes().entrySet()) {
+                Node adjacentNode = adjacencyPair.getKey();
+                Integer edgeWeigh = adjacencyPair.getValue();
+
+                if (!settledNodes.contains(adjacentNode)) {
+                    CalculateMinimumDistance(adjacentNode, edgeWeigh, currentNode);
+                    unsettledNodes.add(adjacentNode);
+                }
+            }
+            settledNodes.add(currentNode);
+        }
+        return graph;
+    }
+
+    private static void CalculateMinimumDistance(Node evaluationNode, Integer edgeWeigh, Node sourceNode) {
+        Integer sourceDistance = sourceNode.getDistance();
+        if (sourceDistance + edgeWeigh < evaluationNode.getDistance()) {
+            evaluationNode.setDistance(sourceDistance + edgeWeigh);
+            LinkedList<Node> shortestPath = new LinkedList<>(sourceNode.getShortestPath());
+            shortestPath.add(sourceNode);
+            evaluationNode.setShortestPath(shortestPath);
+        }
+    }
+
+    private static Node getLowestDistanceNode(Set<Node> unsettledNodes) {
+        Node lowestDistanceNode = null;
+        int lowestDistance = Integer.MAX_VALUE;
+        for (Node node : unsettledNodes) {
+            int nodeDistance = node.getDistance();
+            if (nodeDistance < lowestDistance) {
+                lowestDistance = nodeDistance;
+                lowestDistanceNode = node;
+            }
+        }
+        return lowestDistanceNode;
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/ga/dijkstra/Graph.java

@@ -0,0 +1,21 @@
+package com.baeldung.algorithms.ga.dijkstra;
+
+import java.util.HashSet;
+import java.util.Set;
+
+public class Graph {
+
+    private Set<Node> nodes = new HashSet<>();
+
+    public void addNode(Node nodeA) {
+        nodes.add(nodeA);
+    }
+
+    public Set<Node> getNodes() {
+        return nodes;
+    }
+
+    public void setNodes(Set<Node> nodes) {
+        this.nodes = nodes;
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/ga/dijkstra/Node.java

@@ -0,0 +1,58 @@
+package com.baeldung.algorithms.ga.dijkstra;
+
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+
+public class Node {
+
+    private String name;
+
+    private LinkedList<Node> shortestPath = new LinkedList<>();
+
+    private Integer distance = Integer.MAX_VALUE;
+
+    private Map<Node, Integer> adjacentNodes = new HashMap<>();
+
+    public Node(String name) {
+        this.name = name;
+    }
+
+    public void addDestination(Node destination, int distance) {
+        adjacentNodes.put(destination, distance);
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Map<Node, Integer> getAdjacentNodes() {
+        return adjacentNodes;
+    }
+
+    public void setAdjacentNodes(Map<Node, Integer> adjacentNodes) {
+        this.adjacentNodes = adjacentNodes;
+    }
+
+    public Integer getDistance() {
+        return distance;
+    }
+
+    public void setDistance(Integer distance) {
+        this.distance = distance;
+    }
+
+    public List<Node> getShortestPath() {
+        return shortestPath;
+    }
+
+    public void setShortestPath(LinkedList<Node> shortestPath) {
+        this.shortestPath = shortestPath;
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/linkedlist/CycleDetectionBruteForce.java

@@ -0,0 +1,38 @@
+package com.baeldung.algorithms.linkedlist;
+
+public class CycleDetectionBruteForce {
+
+    public static <T> CycleDetectionResult<T> detectCycle(Node<T> head) {
+        if (head == null) {
+            return new CycleDetectionResult<>(false, null);
+        }
+
+        Node<T> it1 = head;
+        int nodesTraversedByOuter = 0;
+        while (it1 != null && it1.next != null) {
+            it1 = it1.next;
+            nodesTraversedByOuter++;
+
+            int x = nodesTraversedByOuter;
+            Node<T> it2 = head;
+            int noOfTimesCurrentNodeVisited = 0;
+
+            while (x > 0) {
+                it2 = it2.next;
+
+                if (it2 == it1) {
+                    noOfTimesCurrentNodeVisited++;
+                }
+
+                if (noOfTimesCurrentNodeVisited == 2) {
+                    return new CycleDetectionResult<>(true, it1);
+                }
+
+                x--;
+            }
+        }
+
+        return new CycleDetectionResult<>(false, null);
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/linkedlist/CycleDetectionByFastAndSlowIterators.java

@@ -0,0 +1,25 @@
+package com.baeldung.algorithms.linkedlist;
+
+public class CycleDetectionByFastAndSlowIterators {
+
+    public static <T> CycleDetectionResult<T> detectCycle(Node<T> head) {
+        if (head == null) {
+            return new CycleDetectionResult<>(false, null);
+        }
+
+        Node<T> slow = head;
+        Node<T> fast = head;
+
+        while (fast != null && fast.next != null) {
+            slow = slow.next;
+            fast = fast.next.next;
+
+            if (slow == fast) {
+                return new CycleDetectionResult<>(true, fast);
+            }
+        }
+
+        return new CycleDetectionResult<>(false, null);
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/linkedlist/CycleDetectionByHashing.java

@@ -0,0 +1,27 @@
+package com.baeldung.algorithms.linkedlist;
+
+import java.util.HashSet;
+import java.util.Set;
+
+public class CycleDetectionByHashing {
+
+    public static <T> CycleDetectionResult<T> detectCycle(Node<T> head) {
+        if (head == null) {
+            return new CycleDetectionResult<>(false, null);
+        }
+
+        Set<Node<T>> set = new HashSet<>();
+        Node<T> node = head;
+
+        while (node != null) {
+            if (set.contains(node)) {
+                return new CycleDetectionResult<>(true, node);
+            }
+            set.add(node);
+            node = node.next;
+        }
+
+        return new CycleDetectionResult<>(false, null);
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/linkedlist/CycleDetectionResult.java

@@ -0,0 +1,12 @@
+package com.baeldung.algorithms.linkedlist;
+
+public class CycleDetectionResult<T> {
+    boolean cycleExists;
+    Node<T> node;
+
+    public CycleDetectionResult(boolean cycleExists, Node<T> node) {
+        super();
+        this.cycleExists = cycleExists;
+        this.node = node;
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/linkedlist/CycleRemovalBruteForce.java

@@ -0,0 +1,56 @@
+package com.baeldung.algorithms.linkedlist;
+
+public class CycleRemovalBruteForce {
+
+    public static <T> boolean detectAndRemoveCycle(Node<T> head) {
+        CycleDetectionResult<T> result = CycleDetectionByFastAndSlowIterators.detectCycle(head);
+
+        if (result.cycleExists) {
+            removeCycle(result.node, head);
+        }
+
+        return result.cycleExists;
+    }
+
+    /**
+     * @param loopNodeParam - reference to the node where Flyods cycle 
+     * finding algorithm ends, i.e. the fast and the slow iterators
+     * meet.
+     * @param head - reference to the head of the list
+     */
+    private static <T> void removeCycle(Node<T> loopNodeParam, Node<T> head) {
+        Node<T> it = head;
+
+        while (it != null) {
+            if (isNodeReachableFromLoopNode(it, loopNodeParam)) {
+                Node<T> loopStart = it;
+                findEndNodeAndBreakCycle(loopStart);
+                break;
+            }
+            it = it.next;
+        }
+    }
+
+    private static <T> boolean isNodeReachableFromLoopNode(Node<T> it, Node<T> loopNodeParam) {
+        Node<T> loopNode = loopNodeParam;
+
+        do {
+            if (it == loopNode) {
+                return true;
+            }
+            loopNode = loopNode.next;
+        } while (loopNode.next != loopNodeParam);
+
+        return false;
+    }
+
+    private static <T> void findEndNodeAndBreakCycle(Node<T> loopStartParam) {
+        Node<T> loopStart = loopStartParam;
+
+        while (loopStart.next != loopStartParam) {
+            loopStart = loopStart.next;
+        }
+
+        loopStart.next = null;
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/linkedlist/CycleRemovalByCountingLoopNodes.java

@@ -0,0 +1,44 @@
+package com.baeldung.algorithms.linkedlist;
+
+public class CycleRemovalByCountingLoopNodes {
+
+    public static <T> boolean detectAndRemoveCycle(Node<T> head) {
+        CycleDetectionResult<T> result = CycleDetectionByFastAndSlowIterators.detectCycle(head);
+
+        if (result.cycleExists) {
+            removeCycle(result.node, head);
+        }
+
+        return result.cycleExists;
+    }
+
+    private static <T> void removeCycle(Node<T> loopNodeParam, Node<T> head) {
+        int cycleLength = calculateCycleLength(loopNodeParam);
+        Node<T> cycleLengthAdvancedIterator = head;
+        Node<T> it = head;
+
+        for (int i = 0; i < cycleLength; i++) {
+            cycleLengthAdvancedIterator = cycleLengthAdvancedIterator.next;
+        }
+
+        while (it.next != cycleLengthAdvancedIterator.next) {
+            it = it.next;
+            cycleLengthAdvancedIterator = cycleLengthAdvancedIterator.next;
+        }
+
+        cycleLengthAdvancedIterator.next = null;
+    }
+
+    private static <T> int calculateCycleLength(Node<T> loopNodeParam) {
+        Node<T> loopNode = loopNodeParam;
+        int length = 1;
+
+        while (loopNode.next != loopNodeParam) {
+            length++;
+            loopNode = loopNode.next;
+        }
+
+        return length;
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/linkedlist/CycleRemovalWithoutCountingLoopNodes.java

@@ -0,0 +1,27 @@
+package com.baeldung.algorithms.linkedlist;
+
+public class CycleRemovalWithoutCountingLoopNodes {
+
+    public static <T> boolean detectAndRemoveCycle(Node<T> head) {
+        CycleDetectionResult<T> result = CycleDetectionByFastAndSlowIterators.detectCycle(head);
+
+        if (result.cycleExists) {
+            removeCycle(result.node, head);
+        }
+
+        return result.cycleExists;
+    }
+
+    private static <T> void removeCycle(Node<T> meetingPointParam, Node<T> head) {
+        Node<T> loopNode = meetingPointParam;
+        Node<T> it = head;
+
+        while (loopNode.next != it.next) {
+            it = it.next;
+            loopNode = loopNode.next;
+        }
+
+        loopNode.next = null;
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/linkedlist/Node.java

@@ -0,0 +1,38 @@
+package com.baeldung.algorithms.linkedlist;
+
+public class Node<T> {
+    T data;
+    Node<T> next;
+
+    public static <T> Node<T> createNewNode(T data, Node<T> next) {
+        Node<T> node = new Node<T>();
+        node.data = data;
+        node.next = next;
+        return node;
+    }
+
+    public static <T> void traverseList(Node<T> root) {
+        if (root == null) {
+            return;
+        }
+
+        Node<T> node = root;
+        while (node != null) {
+            System.out.println(node.data);
+            node = node.next;
+        }
+    }
+
+    public static <T> Node<T> getTail(Node<T> root) {
+        if (root == null) {
+            return null;
+        }
+
+        Node<T> node = root;
+        while (node.next != null) {
+            node = node.next;
+        }
+        return node;
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/maze/solver/BFSMazeSolver.java

@@ -0,0 +1,52 @@
+package com.baeldung.algorithms.maze.solver;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+
+public class BFSMazeSolver {
+    private static final int[][] DIRECTIONS = { { 0, 1 }, { 1, 0 }, { 0, -1 }, { -1, 0 } };
+
+    public List<Coordinate> solve(Maze maze) {
+        LinkedList<Coordinate> nextToVisit = new LinkedList<>();
+        Coordinate start = maze.getEntry();
+        nextToVisit.add(start);
+
+        while (!nextToVisit.isEmpty()) {
+            Coordinate cur = nextToVisit.remove();
+
+            if (!maze.isValidLocation(cur.getX(), cur.getY()) || maze.isExplored(cur.getX(), cur.getY())) {
+                continue;
+            }
+
+            if (maze.isWall(cur.getX(), cur.getY())) {
+                maze.setVisited(cur.getX(), cur.getY(), true);
+                continue;
+            }
+
+            if (maze.isExit(cur.getX(), cur.getY())) {
+                return backtrackPath(cur);
+            }
+
+            for (int[] direction : DIRECTIONS) {
+                Coordinate coordinate = new Coordinate(cur.getX() + direction[0], cur.getY() + direction[1], cur);
+                nextToVisit.add(coordinate);
+                maze.setVisited(cur.getX(), cur.getY(), true);
+            }
+        }
+        return Collections.emptyList();
+    }
+
+    private List<Coordinate> backtrackPath(Coordinate cur) {
+        List<Coordinate> path = new ArrayList<>();
+        Coordinate iter = cur;
+
+        while (iter != null) {
+            path.add(iter);
+            iter = iter.parent;
+        }
+
+        return path;
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/maze/solver/Coordinate.java

@@ -0,0 +1,31 @@
+package com.baeldung.algorithms.maze.solver;
+
+public class Coordinate {
+    int x;
+    int y;
+    Coordinate parent;
+
+    public Coordinate(int x, int y) {
+        this.x = x;
+        this.y = y;
+        this.parent = null;
+    }
+
+    public Coordinate(int x, int y, Coordinate parent) {
+        this.x = x;
+        this.y = y;
+        this.parent = parent;
+    }
+
+    int getX() {
+        return x;
+    }
+
+    int getY() {
+        return y;
+    }
+
+    Coordinate getParent() {
+        return parent;
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/maze/solver/DFSMazeSolver.java

@@ -0,0 +1,48 @@
+package com.baeldung.algorithms.maze.solver;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class DFSMazeSolver {
+    private static final int[][] DIRECTIONS = { { 0, 1 }, { 1, 0 }, { 0, -1 }, { -1, 0 } };
+
+    public List<Coordinate> solve(Maze maze) {
+        List<Coordinate> path = new ArrayList<>();
+        if (explore(maze, maze.getEntry()
+            .getX(),
+            maze.getEntry()
+                .getY(),
+            path)) {
+            return path;
+        }
+        return Collections.emptyList();
+    }
+
+    private boolean explore(Maze maze, int row, int col, List<Coordinate> path) {
+        if (!maze.isValidLocation(row, col) || maze.isWall(row, col) || maze.isExplored(row, col)) {
+            return false;
+        }
+
+        path.add(new Coordinate(row, col));
+        maze.setVisited(row, col, true);
+
+        if (maze.isExit(row, col)) {
+            return true;
+        }
+
+        for (int[] direction : DIRECTIONS) {
+            Coordinate coordinate = getNextCoordinate(row, col, direction[0], direction[1]);
+            if (explore(maze, coordinate.getX(), coordinate.getY(), path)) {
+                return true;
+            }
+        }
+
+        path.remove(path.size() - 1);
+        return false;
+    }
+
+    private Coordinate getNextCoordinate(int row, int col, int i, int j) {
+        return new Coordinate(row + i, col + j);
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/maze/solver/Maze.java

@@ -0,0 +1,141 @@
+package com.baeldung.algorithms.maze.solver;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Scanner;
+
+public class Maze {
+    private static final int ROAD = 0;
+    private static final int WALL = 1;
+    private static final int START = 2;
+    private static final int EXIT = 3;
+    private static final int PATH = 4;
+
+    private int[][] maze;
+    private boolean[][] visited;
+    private Coordinate start;
+    private Coordinate end;
+
+    public Maze(File maze) throws FileNotFoundException {
+        String fileText = "";
+        try (Scanner input = new Scanner(maze)) {
+            while (input.hasNextLine()) {
+                fileText += input.nextLine() + "\n";
+            }
+        }
+        initializeMaze(fileText);
+    }
+
+    private void initializeMaze(String text) {
+        if (text == null || (text = text.trim()).length() == 0) {
+            throw new IllegalArgumentException("empty lines data");
+        }
+
+        String[] lines = text.split("[\r]?\n");
+        maze = new int[lines.length][lines[0].length()];
+        visited = new boolean[lines.length][lines[0].length()];
+
+        for (int row = 0; row < getHeight(); row++) {
+            if (lines[row].length() != getWidth()) {
+                throw new IllegalArgumentException("line " + (row + 1) + " wrong length (was " + lines[row].length() + " but should be " + getWidth() + ")");
+            }
+
+            for (int col = 0; col < getWidth(); col++) {
+                if (lines[row].charAt(col) == '#')
+                    maze[row][col] = WALL;
+                else if (lines[row].charAt(col) == 'S') {
+                    maze[row][col] = START;
+                    start = new Coordinate(row, col);
+                } else if (lines[row].charAt(col) == 'E') {
+                    maze[row][col] = EXIT;
+                    end = new Coordinate(row, col);
+                } else
+                    maze[row][col] = ROAD;
+            }
+        }
+    }
+
+    public int getHeight() {
+        return maze.length;
+    }
+
+    public int getWidth() {
+        return maze[0].length;
+    }
+
+    public Coordinate getEntry() {
+        return start;
+    }
+
+    public Coordinate getExit() {
+        return end;
+    }
+
+    public boolean isExit(int x, int y) {
+        return x == end.getX() && y == end.getY();
+    }
+
+    public boolean isStart(int x, int y) {
+        return x == start.getX() && y == start.getY();
+    }
+
+    public boolean isExplored(int row, int col) {
+        return visited[row][col];
+    }
+
+    public boolean isWall(int row, int col) {
+        return maze[row][col] == WALL;
+    }
+
+    public void setVisited(int row, int col, boolean value) {
+        visited[row][col] = value;
+    }
+
+    public boolean isValidLocation(int row, int col) {
+        if (row < 0 || row >= getHeight() || col < 0 || col >= getWidth()) {
+            return false;
+        }
+        return true;
+    }
+
+    public void printPath(List<Coordinate> path) {
+        int[][] tempMaze = Arrays.stream(maze)
+            .map(int[]::clone)
+            .toArray(int[][]::new);
+        for (Coordinate coordinate : path) {
+            if (isStart(coordinate.getX(), coordinate.getY()) || isExit(coordinate.getX(), coordinate.getY())) {
+                continue;
+            }
+            tempMaze[coordinate.getX()][coordinate.getY()] = PATH;
+        }
+        System.out.println(toString(tempMaze));
+    }
+
+    public String toString(int[][] maze) {
+        StringBuilder result = new StringBuilder(getWidth() * (getHeight() + 1));
+        for (int row = 0; row < getHeight(); row++) {
+            for (int col = 0; col < getWidth(); col++) {
+                if (maze[row][col] == ROAD) {
+                    result.append(' ');
+                } else if (maze[row][col] == WALL) {
+                    result.append('#');
+                } else if (maze[row][col] == START) {
+                    result.append('S');
+                } else if (maze[row][col] == EXIT) {
+                    result.append('E');
+                } else {
+                    result.append('.');
+                }
+            }
+            result.append('\n');
+        }
+        return result.toString();
+    }
+
+    public void reset() {
+        for (int i = 0; i < visited.length; i++)
+            Arrays.fill(visited[i], false);
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/maze/solver/MazeDriver.java

@@ -0,0 +1,34 @@
+package com.baeldung.algorithms.maze.solver;
+
+import java.io.File;
+import java.util.List;
+
+public class MazeDriver {
+    public static void main(String[] args) throws Exception {
+        File maze1 = new File("src/main/resources/maze/maze1.txt");
+        File maze2 = new File("src/main/resources/maze/maze2.txt");
+
+        execute(maze1);
+        execute(maze2);
+    }
+
+    private static void execute(File file) throws Exception {
+        Maze maze = new Maze(file);
+        dfs(maze);
+        bfs(maze);
+    }
+
+    private static void bfs(Maze maze) {
+        BFSMazeSolver bfs = new BFSMazeSolver();
+        List<Coordinate> path = bfs.solve(maze);
+        maze.printPath(path);
+        maze.reset();
+    }
+
+    private static void dfs(Maze maze) {
+        DFSMazeSolver dfs = new DFSMazeSolver();
+        List<Coordinate> path = dfs.solve(maze);
+        maze.printPath(path);
+        maze.reset();
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/numberwordconverter/NumberWordConverter.java

@@ -0,0 +1,75 @@
+package com.baeldung.algorithms.numberwordconverter;
+
+import java.math.BigDecimal;
+
+import pl.allegro.finance.tradukisto.MoneyConverters;
+
+public class NumberWordConverter {
+
+    public static final String INVALID_INPUT_GIVEN = "Invalid input given";
+
+    public static final String[] ones = { "", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen" };
+
+    public static final String[] tens = {
+      "", // 0
+      "", // 1
+      "twenty", // 2
+      "thirty", // 3
+      "forty", // 4
+      "fifty", // 5
+      "sixty", // 6
+      "seventy", // 7
+      "eighty", // 8
+      "ninety" // 9
+    };
+
+    public static String getMoneyIntoWords(String input) {
+        MoneyConverters converter = MoneyConverters.ENGLISH_BANKING_MONEY_VALUE;
+        return converter.asWords(new BigDecimal(input));
+    }
+
+    public static String getMoneyIntoWords(final double money) {
+        long dollar = (long) money;
+        long cents = Math.round((money - dollar) * 100);
+        if (money == 0D) {
+            return "";
+        }
+        if (money < 0) {
+            return INVALID_INPUT_GIVEN;
+        }
+        String dollarPart = "";
+        if (dollar > 0) {
+            dollarPart = convert(dollar) + " dollar" + (dollar == 1 ? "" : "s");
+        }
+        String centsPart = "";
+        if (cents > 0) {
+            if (dollarPart.length() > 0) {
+                centsPart = " and ";
+            }
+            centsPart += convert(cents) + " cent" + (cents == 1 ? "" : "s");
+        }
+        return dollarPart + centsPart;
+    }
+
+    private static String convert(final long n) {
+        if (n < 0) {
+            return INVALID_INPUT_GIVEN;
+        }
+        if (n < 20) {
+            return ones[(int) n];
+        }
+        if (n < 100) {
+            return tens[(int) n / 10] + ((n % 10 != 0) ? " " : "") + ones[(int) n % 10];
+        }
+        if (n < 1000) {
+            return ones[(int) n / 100] + " hundred" + ((n % 100 != 0) ? " " : "") + convert(n % 100);
+        }
+        if (n < 1_000_000) {
+            return convert(n / 1000) + " thousand" + ((n % 1000 != 0) ? " " : "") + convert(n % 1000);
+        }
+        if (n < 1_000_000_000) {
+            return convert(n / 1_000_000) + " million" + ((n % 1_000_000 != 0) ? " " : "") + convert(n % 1_000_000);
+        }
+        return convert(n / 1_000_000_000) + " billion" + ((n % 1_000_000_000 != 0) ? " " : "") + convert(n % 1_000_000_000);
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/slope_one/InputData.java

@@ -0,0 +1,35 @@
+package com.baeldung.algorithms.slope_one;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import lombok.Data;
+
+@Data
+public class InputData {
+
+    protected static List<Item> items = Arrays.asList(new Item("Candy"), new Item("Drink"), new Item("Soda"), new Item("Popcorn"), new Item("Snacks"));
+
+    public static Map<User, HashMap<Item, Double>> initializeData(int numberOfUsers) {
+        Map<User, HashMap<Item, Double>> data = new HashMap<>();
+        HashMap<Item, Double> newUser;
+        Set<Item> newRecommendationSet;
+        for (int i = 0; i < numberOfUsers; i++) {
+            newUser = new HashMap<Item, Double>();
+            newRecommendationSet = new HashSet<>();
+            for (int j = 0; j < 3; j++) {
+                newRecommendationSet.add(items.get((int) (Math.random() * 5)));
+            }
+            for (Item item : newRecommendationSet) {
+                newUser.put(item, Math.random());
+            }
+            data.put(new User("User " + i), newUser);
+        }
+        return data;
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/slope_one/Item.java

@@ -0,0 +1,13 @@
+package com.baeldung.algorithms.slope_one;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+public class Item {
+
+    private String itemName;
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/slope_one/SlopeOne.java

@@ -0,0 +1,124 @@
+package com.baeldung.algorithms.slope_one;
+
+import java.text.DecimalFormat;
+import java.text.NumberFormat;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+
+/**
+ * Slope One algorithm implementation
+ */
+public class SlopeOne {
+
+    private static Map<Item, Map<Item, Double>> diff = new HashMap<>();
+    private static Map<Item, Map<Item, Integer>> freq = new HashMap<>();
+    private static Map<User, HashMap<Item, Double>> inputData;
+    private static Map<User, HashMap<Item, Double>> outputData = new HashMap<>();
+
+    public static void slopeOne(int numberOfUsers) {
+        inputData = InputData.initializeData(numberOfUsers);
+        System.out.println("Slope One - Before the Prediction\n");
+        buildDifferencesMatrix(inputData);
+        System.out.println("\nSlope One - With Predictions\n");
+        predict(inputData);
+    }
+
+    /**
+     * Based on the available data, calculate the relationships between the
+     * items and number of occurences
+     * 
+     * @param data
+     *            existing user data and their items' ratings
+     */
+    private static void buildDifferencesMatrix(Map<User, HashMap<Item, Double>> data) {
+        for (HashMap<Item, Double> user : data.values()) {
+            for (Entry<Item, Double> e : user.entrySet()) {
+                if (!diff.containsKey(e.getKey())) {
+                    diff.put(e.getKey(), new HashMap<Item, Double>());
+                    freq.put(e.getKey(), new HashMap<Item, Integer>());
+                }
+                for (Entry<Item, Double> e2 : user.entrySet()) {
+                    int oldCount = 0;
+                    if (freq.get(e.getKey()).containsKey(e2.getKey())) {
+                        oldCount = freq.get(e.getKey()).get(e2.getKey()).intValue();
+                    }
+                    double oldDiff = 0.0;
+                    if (diff.get(e.getKey()).containsKey(e2.getKey())) {
+                        oldDiff = diff.get(e.getKey()).get(e2.getKey()).doubleValue();
+                    }
+                    double observedDiff = e.getValue() - e2.getValue();
+                    freq.get(e.getKey()).put(e2.getKey(), oldCount + 1);
+                    diff.get(e.getKey()).put(e2.getKey(), oldDiff + observedDiff);
+                }
+            }
+        }
+        for (Item j : diff.keySet()) {
+            for (Item i : diff.get(j).keySet()) {
+                double oldValue = diff.get(j).get(i).doubleValue();
+                int count = freq.get(j).get(i).intValue();
+                diff.get(j).put(i, oldValue / count);
+            }
+        }
+        printData(data);
+    }
+
+    /**
+     * Based on existing data predict all missing ratings. If prediction is not
+     * possible, the value will be equal to -1
+     * 
+     * @param data
+     *            existing user data and their items' ratings
+     */
+    private static void predict(Map<User, HashMap<Item, Double>> data) {
+        HashMap<Item, Double> uPred = new HashMap<Item, Double>();
+        HashMap<Item, Integer> uFreq = new HashMap<Item, Integer>();
+        for (Item j : diff.keySet()) {
+            uFreq.put(j, 0);
+            uPred.put(j, 0.0);
+        }
+        for (Entry<User, HashMap<Item, Double>> e : data.entrySet()) {
+            for (Item j : e.getValue().keySet()) {
+                for (Item k : diff.keySet()) {
+                    try {
+                        double predictedValue = diff.get(k).get(j).doubleValue() + e.getValue().get(j).doubleValue();
+                        double finalValue = predictedValue * freq.get(k).get(j).intValue();
+                        uPred.put(k, uPred.get(k) + finalValue);
+                        uFreq.put(k, uFreq.get(k) + freq.get(k).get(j).intValue());
+                    } catch (NullPointerException e1) {
+                    }
+                }
+            }
+            HashMap<Item, Double> clean = new HashMap<Item, Double>();
+            for (Item j : uPred.keySet()) {
+                if (uFreq.get(j) > 0) {
+                    clean.put(j, uPred.get(j).doubleValue() / uFreq.get(j).intValue());
+                }
+            }
+            for (Item j : InputData.items) {
+                if (e.getValue().containsKey(j)) {
+                    clean.put(j, e.getValue().get(j));
+                } else if (!clean.containsKey(j)) {
+                    clean.put(j, -1.0);
+                }
+            }
+            outputData.put(e.getKey(), clean);
+        }
+        printData(outputData);
+    }
+
+    private static void printData(Map<User, HashMap<Item, Double>> data) {
+        for (User user : data.keySet()) {
+            System.out.println(user.getUsername() + ":");
+            print(data.get(user));
+        }
+    }
+
+    private static void print(HashMap<Item, Double> hashMap) {
+        NumberFormat formatter = new DecimalFormat("#0.000");
+        for (Item j : hashMap.keySet()) {
+            System.out.println(" " + j.getItemName() + " --> " + formatter.format(hashMap.get(j).doubleValue()));
+        }
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/slope_one/User.java

@@ -0,0 +1,14 @@
+package com.baeldung.algorithms.slope_one;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+public class User {
+
+    private String username;
+
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/sudoku/BacktrackingAlgorithm.java

@@ -0,0 +1,104 @@
+package com.baeldung.algorithms.sudoku;
+
+import java.util.stream.IntStream;
+
+public class BacktrackingAlgorithm {
+
+    private static final int BOARD_SIZE = 9;
+    private static final int SUBSECTION_SIZE = 3;
+    private static final int BOARD_START_INDEX = 0;
+
+    private static final int NO_VALUE = 0;
+    private static final int MIN_VALUE = 1;
+    private static final int MAX_VALUE = 9;
+
+    private static int[][] board = {
+      {8, 0, 0, 0, 0, 0, 0, 0, 0},
+      {0, 0, 3, 6, 0, 0, 0, 0, 0},
+      {0, 7, 0, 0, 9, 0, 2, 0, 0},
+      {0, 5, 0, 0, 0, 7, 0, 0, 0},
+      {0, 0, 0, 0, 4, 5, 7, 0, 0},
+      {0, 0, 0, 1, 0, 0, 0, 3, 0},
+      {0, 0, 1, 0, 0, 0, 0, 6, 8},
+      {0, 0, 8, 5, 0, 0, 0, 1, 0},
+      {0, 9, 0, 0, 0, 0, 4, 0, 0}
+    };
+
+    public static void main(String[] args) {
+        BacktrackingAlgorithm solver = new BacktrackingAlgorithm();
+        solver.solve(board);
+        solver.printBoard();
+    }
+
+    private void printBoard() {
+        for (int row = BOARD_START_INDEX; row < BOARD_SIZE; row++) {
+            for (int column = BOARD_START_INDEX; column < BOARD_SIZE; column++) {
+                System.out.print(board[row][column] + " ");
+            }
+            System.out.println();
+        }
+    }
+
+    private boolean solve(int[][] board) {
+        for (int row = BOARD_START_INDEX; row < BOARD_SIZE; row++) {
+            for (int column = BOARD_START_INDEX; column < BOARD_SIZE; column++) {
+                if (board[row][column] == NO_VALUE) {
+                    for (int k = MIN_VALUE; k <= MAX_VALUE; k++) {
+                        board[row][column] = k;
+                        if (isValid(board, row, column) && solve(board)) {
+                            return true;
+                        }
+                        board[row][column] = NO_VALUE;
+                    }
+                    return false;
+                }
+            }
+        }
+        return true;
+    }
+
+    private boolean isValid(int[][] board, int row, int column) {
+        return rowConstraint(board, row) &&
+          columnConstraint(board, column) &&
+          subsectionConstraint(board, row, column);
+    }
+
+    private boolean subsectionConstraint(int[][] board, int row, int column) {
+        boolean[] constraint = new boolean[BOARD_SIZE];
+        int subsectionRowStart = (row / SUBSECTION_SIZE) * SUBSECTION_SIZE;
+        int subsectionRowEnd = subsectionRowStart + SUBSECTION_SIZE;
+
+        int subsectionColumnStart = (column / SUBSECTION_SIZE) * SUBSECTION_SIZE;
+        int subsectionColumnEnd = subsectionColumnStart + SUBSECTION_SIZE;
+
+        for (int r = subsectionRowStart; r < subsectionRowEnd; r++) {
+            for (int c = subsectionColumnStart; c < subsectionColumnEnd; c++) {
+                if (!checkConstraint(board, r, constraint, c)) return false;
+            }
+        }
+        return true;
+    }
+
+    private boolean columnConstraint(int[][] board, int column) {
+        boolean[] constraint = new boolean[BOARD_SIZE];
+        return IntStream.range(BOARD_START_INDEX, BOARD_SIZE)
+          .allMatch(row -> checkConstraint(board, row, constraint, column));
+    }
+
+    private boolean rowConstraint(int[][] board, int row) {
+        boolean[] constraint = new boolean[BOARD_SIZE];
+        return IntStream.range(BOARD_START_INDEX, BOARD_SIZE)
+          .allMatch(column -> checkConstraint(board, row, constraint, column));
+    }
+
+    private boolean checkConstraint(int[][] board, int row, boolean[] constraint, int column) {
+        if (board[row][column] != NO_VALUE) {
+            if (!constraint[board[row][column] - 1]) {
+                constraint[board[row][column] - 1] = true;
+            } else {
+                return false;
+            }
+        }
+        return true;
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/sudoku/ColumnNode.java

@@ -0,0 +1,33 @@
+package com.baeldung.algorithms.sudoku;
+
+class ColumnNode extends DancingNode {
+    int size;
+    String name;
+
+    ColumnNode(String n) {
+        super();
+        size = 0;
+        name = n;
+        C = this;
+    }
+
+    void cover() {
+        unlinkLR();
+        for (DancingNode i = this.D; i != this; i = i.D) {
+            for (DancingNode j = i.R; j != i; j = j.R) {
+                j.unlinkUD();
+                j.C.size--;
+            }
+        }
+    }
+
+    void uncover() {
+        for (DancingNode i = this.U; i != this; i = i.U) {
+            for (DancingNode j = i.L; j != i; j = j.L) {
+                j.C.size++;
+                j.relinkUD();
+            }
+        }
+        relinkLR();
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/sudoku/DancingLinks.java

@@ -0,0 +1,133 @@
+package com.baeldung.algorithms.sudoku;
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+
+public class DancingLinks {
+
+    private ColumnNode header;
+    private List<DancingNode> answer;
+
+    private void search(int k) {
+        if (header.R == header) {
+            handleSolution(answer);
+        } else {
+            ColumnNode c = selectColumnNodeHeuristic();
+            c.cover();
+
+            for (DancingNode r = c.D; r != c; r = r.D) {
+                answer.add(r);
+
+                for (DancingNode j = r.R; j != r; j = j.R) {
+                    j.C.cover();
+                }
+
+                search(k + 1);
+
+                r = answer.remove(answer.size() - 1);
+                c = r.C;
+
+                for (DancingNode j = r.L; j != r; j = j.L) {
+                    j.C.uncover();
+                }
+            }
+            c.uncover();
+        }
+    }
+
+    private ColumnNode selectColumnNodeHeuristic() {
+        int min = Integer.MAX_VALUE;
+        ColumnNode ret = null;
+        for (ColumnNode c = (ColumnNode) header.R; c != header; c = (ColumnNode) c.R) {
+            if (c.size < min) {
+                min = c.size;
+                ret = c;
+            }
+        }
+        return ret;
+    }
+
+    private ColumnNode makeDLXBoard(boolean[][] grid) {
+        final int COLS = grid[0].length;
+
+        ColumnNode headerNode = new ColumnNode("header");
+        List<ColumnNode> columnNodes = new ArrayList<>();
+
+        for (int i = 0; i < COLS; i++) {
+            ColumnNode n = new ColumnNode(Integer.toString(i));
+            columnNodes.add(n);
+            headerNode = (ColumnNode) headerNode.hookRight(n);
+        }
+        headerNode = headerNode.R.C;
+
+        for (boolean[] aGrid : grid) {
+            DancingNode prev = null;
+            for (int j = 0; j < COLS; j++) {
+                if (aGrid[j]) {
+                    ColumnNode col = columnNodes.get(j);
+                    DancingNode newNode = new DancingNode(col);
+                    if (prev == null)
+                        prev = newNode;
+                    col.U.hookDown(newNode);
+                    prev = prev.hookRight(newNode);
+                    col.size++;
+                }
+            }
+        }
+
+        headerNode.size = COLS;
+
+        return headerNode;
+    }
+
+    DancingLinks(boolean[][] cover) {
+        header = makeDLXBoard(cover);
+    }
+
+    public void runSolver() {
+        answer = new LinkedList<>();
+        search(0);
+    }
+
+    private void handleSolution(List<DancingNode> answer) {
+        int[][] result = parseBoard(answer);
+        printSolution(result);
+    }
+
+    private int size = 9;
+
+    private int[][] parseBoard(List<DancingNode> answer) {
+        int[][] result = new int[size][size];
+        for (DancingNode n : answer) {
+            DancingNode rcNode = n;
+            int min = Integer.parseInt(rcNode.C.name);
+            for (DancingNode tmp = n.R; tmp != n; tmp = tmp.R) {
+                int val = Integer.parseInt(tmp.C.name);
+                if (val < min) {
+                    min = val;
+                    rcNode = tmp;
+                }
+            }
+            int ans1 = Integer.parseInt(rcNode.C.name);
+            int ans2 = Integer.parseInt(rcNode.R.C.name);
+            int r = ans1 / size;
+            int c = ans1 % size;
+            int num = (ans2 % size) + 1;
+            result[r][c] = num;
+        }
+        return result;
+    }
+
+    private static void printSolution(int[][] result) {
+        int size = result.length;
+        for (int[] aResult : result) {
+            StringBuilder ret = new StringBuilder();
+            for (int j = 0; j < size; j++) {
+                ret.append(aResult[j]).append(" ");
+            }
+            System.out.println(ret);
+        }
+        System.out.println();
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/sudoku/DancingLinksAlgorithm.java

@@ -0,0 +1,121 @@
+package com.baeldung.algorithms.sudoku;
+
+import java.util.Arrays;
+
+public class DancingLinksAlgorithm {
+    private static final int BOARD_SIZE = 9;
+    private static final int SUBSECTION_SIZE = 3;
+    private static final int NO_VALUE = 0;
+    private static final int CONSTRAINTS = 4;
+    private static final int MIN_VALUE = 1;
+    private static final int MAX_VALUE = 9;
+    private static final int COVER_START_INDEX = 1;
+
+    private static int[][] board = {
+      {8, 0, 0, 0, 0, 0, 0, 0, 0},
+      {0, 0, 3, 6, 0, 0, 0, 0, 0},
+      {0, 7, 0, 0, 9, 0, 2, 0, 0},
+      {0, 5, 0, 0, 0, 7, 0, 0, 0},
+      {0, 0, 0, 0, 4, 5, 7, 0, 0},
+      {0, 0, 0, 1, 0, 0, 0, 3, 0},
+      {0, 0, 1, 0, 0, 0, 0, 6, 8},
+      {0, 0, 8, 5, 0, 0, 0, 1, 0},
+      {0, 9, 0, 0, 0, 0, 4, 0, 0}
+    };
+
+    public static void main(String[] args) {
+        DancingLinksAlgorithm solver = new DancingLinksAlgorithm();
+        solver.solve(board);
+    }
+
+    private void solve(int[][] board) {
+        boolean[][] cover = initializeExactCoverBoard(board);
+        DancingLinks dlx = new DancingLinks(cover);
+        dlx.runSolver();
+    }
+
+    private int getIndex(int row, int column, int num) {
+        return (row - 1) * BOARD_SIZE * BOARD_SIZE + (column - 1) * BOARD_SIZE + (num - 1);
+    }
+
+    private boolean[][] createExactCoverBoard() {
+        boolean[][] coverBoard = new boolean[BOARD_SIZE * BOARD_SIZE * MAX_VALUE][BOARD_SIZE * BOARD_SIZE * CONSTRAINTS];
+
+        int hBase = 0;
+        hBase = checkCellConstraint(coverBoard, hBase);
+        hBase = checkRowConstraint(coverBoard, hBase);
+        hBase = checkColumnConstraint(coverBoard, hBase);
+        checkSubsectionConstraint(coverBoard, hBase);
+        
+        return coverBoard;
+    }
+
+    private int checkSubsectionConstraint(boolean[][] coverBoard, int hBase) {
+        for (int row = COVER_START_INDEX; row <= BOARD_SIZE; row += SUBSECTION_SIZE) {
+            for (int column = COVER_START_INDEX; column <= BOARD_SIZE; column += SUBSECTION_SIZE) {
+                for (int n = COVER_START_INDEX; n <= BOARD_SIZE; n++, hBase++) {
+                    for (int rowDelta = 0; rowDelta < SUBSECTION_SIZE; rowDelta++) {
+                        for (int columnDelta = 0; columnDelta < SUBSECTION_SIZE; columnDelta++) {
+                            int index = getIndex(row + rowDelta, column + columnDelta, n);
+                            coverBoard[index][hBase] = true;
+                        }
+                    }
+                }
+            }
+        }
+        return hBase;
+    }
+
+    private int checkColumnConstraint(boolean[][] coverBoard, int hBase) {
+        for (int column = COVER_START_INDEX; column <= BOARD_SIZE; column++) {
+            for (int n = COVER_START_INDEX; n <= BOARD_SIZE; n++, hBase++) {
+                for (int row = COVER_START_INDEX; row <= BOARD_SIZE; row++) {
+                    int index = getIndex(row, column, n);
+                    coverBoard[index][hBase] = true;
+                }
+            }
+        }
+        return hBase;
+    }
+
+    private int checkRowConstraint(boolean[][] coverBoard, int hBase) {
+        for (int row = COVER_START_INDEX; row <= BOARD_SIZE; row++) {
+            for (int n = COVER_START_INDEX; n <= BOARD_SIZE; n++, hBase++) {
+                for (int column = COVER_START_INDEX; column <= BOARD_SIZE; column++) {
+                    int index = getIndex(row, column, n);
+                    coverBoard[index][hBase] = true;
+                }
+            }
+        }
+        return hBase;
+    }
+
+    private int checkCellConstraint(boolean[][] coverBoard, int hBase) {
+        for (int row = COVER_START_INDEX; row <= BOARD_SIZE; row++) {
+            for (int column = COVER_START_INDEX; column <= BOARD_SIZE; column++, hBase++) {
+                for (int n = COVER_START_INDEX; n <= BOARD_SIZE; n++) {
+                    int index = getIndex(row, column, n);
+                    coverBoard[index][hBase] = true;
+                }
+            }
+        }
+        return hBase;
+    }
+
+    private boolean[][] initializeExactCoverBoard(int[][] board) {
+        boolean[][] coverBoard = createExactCoverBoard();
+        for (int row = COVER_START_INDEX; row <= BOARD_SIZE; row++) {
+            for (int column = COVER_START_INDEX; column <= BOARD_SIZE; column++) {
+                int n = board[row - 1][column - 1];
+                if (n != NO_VALUE) {
+                    for (int num = MIN_VALUE; num <= MAX_VALUE; num++) {
+                        if (num != n) {
+                            Arrays.fill(coverBoard[getIndex(row, column, num)], false);
+                        }
+                    }
+                }
+            }
+        }
+        return coverBoard;
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/sudoku/DancingNode.java

@@ -0,0 +1,50 @@
+package com.baeldung.algorithms.sudoku;
+
+class DancingNode {
+    DancingNode L, R, U, D;
+    ColumnNode C;
+
+    DancingNode hookDown(DancingNode node) {
+        assert (this.C == node.C);
+        node.D = this.D;
+        node.D.U = node;
+        node.U = this;
+        this.D = node;
+        return node;
+    }
+
+    DancingNode hookRight(DancingNode node) {
+        node.R = this.R;
+        node.R.L = node;
+        node.L = this;
+        this.R = node;
+        return node;
+    }
+
+    void unlinkLR() {
+        this.L.R = this.R;
+        this.R.L = this.L;
+    }
+
+    void relinkLR() {
+        this.L.R = this.R.L = this;
+    }
+
+    void unlinkUD() {
+        this.U.D = this.D;
+        this.D.U = this.U;
+    }
+
+    void relinkUD() {
+        this.U.D = this.D.U = this;
+    }
+
+    DancingNode() {
+        L = R = U = D = this;
+    }
+
+    DancingNode(ColumnNode c) {
+        this();
+        C = c;
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/main/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

algorithms-modules/algorithms-miscellaneous-2/src/main/resources/maze/maze1.txt

@@ -0,0 +1,12 @@
+S ########
+#        #
+# ### ## #
+# #    # #
+# #  # # #
+# ## #####
+# #      #
+# # #  # #
+##### ####
+#   #    E
+# #    # #
+##########

algorithms-modules/algorithms-miscellaneous-2/src/main/resources/maze/maze2.txt

@@ -0,0 +1,22 @@
+S ##########################
+# #      #                 #
+# # ####   ############### #
+# # #    # #               #
+# # #### # # ###############
+# # #    # # #             #
+# # # #### ### ########### #
+# # # #        #           #
+#       ################## #
+#########    # # #       # #
+# #       #### # ####### # #
+# # ### ###  # # #       # #
+#   #       ##   # ##### # #
+##### #######  # #     # # #
+#     #       ## ## #### # #
+# ##### #######     #      #
+#       #       ############
+####### #########        # #
+#       #         ######## #
+# ####### ###### ##   #    E
+#         #         #   ## #
+############################

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/DijkstraAlgorithmLongRunningUnitTest.java

@@ -0,0 +1,86 @@
+package com.baeldung.algorithms;
+
+import org.junit.Test;
+
+import com.baeldung.algorithms.ga.dijkstra.Dijkstra;
+import com.baeldung.algorithms.ga.dijkstra.Graph;
+import com.baeldung.algorithms.ga.dijkstra.Node;
+
+import java.util.Arrays;
+import java.util.List;
+
+import static org.junit.Assert.assertTrue;
+
+public class DijkstraAlgorithmLongRunningUnitTest {
+
+    @Test
+    public void whenSPPSolved_thenCorrect() {
+
+        Node nodeA = new Node("A");
+        Node nodeB = new Node("B");
+        Node nodeC = new Node("C");
+        Node nodeD = new Node("D");
+        Node nodeE = new Node("E");
+        Node nodeF = new Node("F");
+
+        nodeA.addDestination(nodeB, 10);
+        nodeA.addDestination(nodeC, 15);
+
+        nodeB.addDestination(nodeD, 12);
+        nodeB.addDestination(nodeF, 15);
+
+        nodeC.addDestination(nodeE, 10);
+
+        nodeD.addDestination(nodeE, 2);
+        nodeD.addDestination(nodeF, 1);
+
+        nodeF.addDestination(nodeE, 5);
+
+        Graph graph = new Graph();
+
+        graph.addNode(nodeA);
+        graph.addNode(nodeB);
+        graph.addNode(nodeC);
+        graph.addNode(nodeD);
+        graph.addNode(nodeE);
+        graph.addNode(nodeF);
+
+        graph = Dijkstra.calculateShortestPathFromSource(graph, nodeA);
+
+        List<Node> shortestPathForNodeB = Arrays.asList(nodeA);
+        List<Node> shortestPathForNodeC = Arrays.asList(nodeA);
+        List<Node> shortestPathForNodeD = Arrays.asList(nodeA, nodeB);
+        List<Node> shortestPathForNodeE = Arrays.asList(nodeA, nodeB, nodeD);
+        List<Node> shortestPathForNodeF = Arrays.asList(nodeA, nodeB, nodeD);
+
+        for (Node node : graph.getNodes()) {
+            switch (node.getName()) {
+            case "B":
+                assertTrue(node
+                  .getShortestPath()
+                  .equals(shortestPathForNodeB));
+                break;
+            case "C":
+                assertTrue(node
+                  .getShortestPath()
+                  .equals(shortestPathForNodeC));
+                break;
+            case "D":
+                assertTrue(node
+                  .getShortestPath()
+                  .equals(shortestPathForNodeD));
+                break;
+            case "E":
+                assertTrue(node
+                  .getShortestPath()
+                  .equals(shortestPathForNodeE));
+                break;
+            case "F":
+                assertTrue(node
+                  .getShortestPath()
+                  .equals(shortestPathForNodeF));
+                break;
+            }
+        }
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/astar/Graph.java

@@ -0,0 +1,30 @@
+package com.baeldung.algorithms.astar;
+
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+
+public class Graph<T extends GraphNode> {
+    private final Set<T> nodes;
+
+    private final Map<String, Set<String>> connections;
+
+    public Graph(Set<T> nodes, Map<String, Set<String>> connections) {
+        this.nodes = nodes;
+        this.connections = connections;
+    }
+
+    public T getNode(String id) {
+        return nodes.stream()
+            .filter(node -> node.getId().equals(id))
+            .findFirst()
+            .orElseThrow(() -> new IllegalArgumentException("No node found with ID"));
+    }
+
+    public Set<T> getConnections(T node) {
+        return connections.get(node.getId()).stream()
+            .map(this::getNode)
+            .collect(Collectors.toSet());
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/astar/GraphNode.java

@@ -0,0 +1,5 @@
+package com.baeldung.algorithms.astar;
+
+public interface GraphNode {
+    String getId();
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/astar/RouteFinder.java

@@ -0,0 +1,69 @@
+package com.baeldung.algorithms.astar;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.PriorityQueue;
+import java.util.Queue;
+import java.util.stream.Collectors;
+
+import lombok.extern.slf4j.Slf4j;
+
+@Slf4j
+public class RouteFinder<T extends GraphNode> {
+    private final Graph<T> graph;
+    private final Scorer<T> nextNodeScorer;
+    private final Scorer<T> targetScorer;
+
+    public RouteFinder(Graph<T> graph, Scorer<T> nextNodeScorer, Scorer<T> targetScorer) {
+        this.graph = graph;
+        this.nextNodeScorer = nextNodeScorer;
+        this.targetScorer = targetScorer;
+    }
+
+    public List<T> findRoute(T from, T to) {
+        Map<T, RouteNode<T>> allNodes = new HashMap<>();
+        Queue<RouteNode> openSet = new PriorityQueue<>();
+
+        RouteNode<T> start = new RouteNode<>(from, null, 0d, targetScorer.computeCost(from, to));
+        allNodes.put(from, start);
+        openSet.add(start);
+
+        while (!openSet.isEmpty()) {
+            log.debug("Open Set contains: " + openSet.stream().map(RouteNode::getCurrent).collect(Collectors.toSet()));
+            RouteNode<T> next = openSet.poll();
+            log.debug("Looking at node: " + next);
+            if (next.getCurrent().equals(to)) {
+                log.debug("Found our destination!");
+
+                List<T> route = new ArrayList<>();
+                RouteNode<T> current = next;
+                do {
+                    route.add(0, current.getCurrent());
+                    current = allNodes.get(current.getPrevious());
+                } while (current != null);
+
+                log.debug("Route: " + route);
+                return route;
+            }
+
+            graph.getConnections(next.getCurrent()).forEach(connection -> {
+                double newScore = next.getRouteScore() + nextNodeScorer.computeCost(next.getCurrent(), connection);
+                RouteNode<T> nextNode = allNodes.getOrDefault(connection, new RouteNode<>(connection));
+                allNodes.put(connection, nextNode);
+
+                if (nextNode.getRouteScore() > newScore) {
+                    nextNode.setPrevious(next.getCurrent());
+                    nextNode.setRouteScore(newScore);
+                    nextNode.setEstimatedScore(newScore + targetScorer.computeCost(connection, to));
+                    openSet.add(nextNode);
+                    log.debug("Found a better route to node: " + nextNode);
+                }
+            });
+        }
+
+        throw new IllegalStateException("No route found");
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/astar/RouteNode.java

@@ -0,0 +1,67 @@
+package com.baeldung.algorithms.astar;
+
+import java.util.StringJoiner;
+
+class RouteNode<T extends GraphNode> implements Comparable<RouteNode> {
+    private final T current;
+    private T previous;
+    private double routeScore;
+    private double estimatedScore;
+
+    RouteNode(T current) {
+        this(current, null, Double.POSITIVE_INFINITY, Double.POSITIVE_INFINITY);
+    }
+
+    RouteNode(T current, T previous, double routeScore, double estimatedScore) {
+        this.current = current;
+        this.previous = previous;
+        this.routeScore = routeScore;
+        this.estimatedScore = estimatedScore;
+    }
+
+    T getCurrent() {
+        return current;
+    }
+
+    T getPrevious() {
+        return previous;
+    }
+
+    double getRouteScore() {
+        return routeScore;
+    }
+
+    double getEstimatedScore() {
+        return estimatedScore;
+    }
+
+    void setPrevious(T previous) {
+        this.previous = previous;
+    }
+
+    void setRouteScore(double routeScore) {
+        this.routeScore = routeScore;
+    }
+
+    void setEstimatedScore(double estimatedScore) {
+        this.estimatedScore = estimatedScore;
+    }
+
+    @Override
+    public int compareTo(RouteNode other) {
+        if (this.estimatedScore > other.estimatedScore) {
+            return 1;
+        } else if (this.estimatedScore < other.estimatedScore) {
+            return -1;
+        } else {
+            return 0;
+        }
+    }
+
+    @Override
+    public String toString() {
+        return new StringJoiner(", ", RouteNode.class.getSimpleName() + "[", "]").add("current=" + current)
+            .add("previous=" + previous).add("routeScore=" + routeScore).add("estimatedScore=" + estimatedScore)
+            .toString();
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/astar/Scorer.java

@@ -0,0 +1,5 @@
+package com.baeldung.algorithms.astar;
+
+public interface Scorer<T extends GraphNode> {
+    double computeCost(T from, T to);
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/astar/underground/HaversineScorer.java

@@ -0,0 +1,19 @@
+package com.baeldung.algorithms.astar.underground;
+
+import com.baeldung.algorithms.astar.Scorer;
+
+public class HaversineScorer implements Scorer<Station> {
+    @Override
+    public double computeCost(Station from, Station to) {
+        double R = 6372.8; // In kilometers
+
+        double dLat = Math.toRadians(to.getLatitude() - from.getLatitude());
+        double dLon = Math.toRadians(to.getLongitude() - from.getLongitude());
+        double lat1 = Math.toRadians(from.getLatitude());
+        double lat2 = Math.toRadians(to.getLatitude());
+
+        double a = Math.pow(Math.sin(dLat / 2),2) + Math.pow(Math.sin(dLon / 2),2) * Math.cos(lat1) * Math.cos(lat2);
+        double c = 2 * Math.asin(Math.sqrt(a));
+        return R * c;
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/astar/underground/RouteFinderIntegrationTest.java

@@ -0,0 +1,650 @@
+package com.baeldung.algorithms.astar.underground;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import com.baeldung.algorithms.astar.Graph;
+import com.baeldung.algorithms.astar.RouteFinder;
+
+import lombok.extern.slf4j.Slf4j;
+
+import org.junit.Before;
+import org.junit.Test;
+
+@Slf4j
+public class RouteFinderIntegrationTest {
+
+    private Graph<Station> underground;
+
+    private RouteFinder<Station> routeFinder;
+
+    @Before
+    public void setUp() throws Exception {
+        Set<Station> stations = new HashSet<>();
+        Map<String, Set<String>> connections = new HashMap<>();
+
+        stations.add(new Station("1", "Acton Town", 51.5028, -0.2801));
+        stations.add(new Station("2", "Aldgate", 51.5143, -0.0755));
+        stations.add(new Station("3", "Aldgate East", 51.5154, -0.0726));
+        stations.add(new Station("4", "All Saints", 51.5107, -0.013));
+        stations.add(new Station("5", "Alperton", 51.5407, -0.2997));
+        stations.add(new Station("6", "Amersham", 51.6736, -0.607));
+        stations.add(new Station("7", "Angel", 51.5322, -0.1058));
+        stations.add(new Station("8", "Archway", 51.5653, -0.1353));
+        stations.add(new Station("9", "Arnos Grove", 51.6164, -0.1331));
+        stations.add(new Station("10", "Arsenal", 51.5586, -0.1059));
+        stations.add(new Station("11", "Baker Street", 51.5226, -0.1571));
+        stations.add(new Station("12", "Balham", 51.4431, -0.1525));
+        stations.add(new Station("13", "Bank", 51.5133, -0.0886));
+        stations.add(new Station("14", "Barbican", 51.5204, -0.0979));
+        stations.add(new Station("15", "Barking", 51.5396, 0.081));
+        stations.add(new Station("16", "Barkingside", 51.5856, 0.0887));
+        stations.add(new Station("17", "Barons Court", 51.4905, -0.2139));
+        stations.add(new Station("18", "Bayswater", 51.5121, -0.1879));
+        stations.add(new Station("19", "Beckton", 51.5148, 0.0613));
+        stations.add(new Station("20", "Beckton Park", 51.5087, 0.055));
+        stations.add(new Station("21", "Becontree", 51.5403, 0.127));
+        stations.add(new Station("22", "Belsize Park", 51.5504, -0.1642));
+        stations.add(new Station("23", "Bermondsey", 51.4979, -0.0637));
+        stations.add(new Station("24", "Bethnal Green", 51.527, -0.0549));
+        stations.add(new Station("25", "Blackfriars", 51.512, -0.1031));
+        stations.add(new Station("26", "Blackhorse Road", 51.5867, -0.0417));
+        stations.add(new Station("27", "Blackwall", 51.5079, -0.0066));
+        stations.add(new Station("28", "Bond Street", 51.5142, -0.1494));
+        stations.add(new Station("29", "Borough", 51.5011, -0.0943));
+        stations.add(new Station("30", "Boston Manor", 51.4956, -0.325));
+        stations.add(new Station("31", "Bounds Green", 51.6071, -0.1243));
+        stations.add(new Station("32", "Bow Church", 51.5273, -0.0208));
+        stations.add(new Station("33", "Bow Road", 51.5269, -0.0247));
+        stations.add(new Station("34", "Brent Cross", 51.5766, -0.2136));
+        stations.add(new Station("35", "Brixton", 51.4627, -0.1145));
+        stations.add(new Station("36", "Bromley-By-Bow", 51.5248, -0.0119));
+        stations.add(new Station("37", "Buckhurst Hill", 51.6266, 0.0471));
+        stations.add(new Station("38", "Burnt Oak", 51.6028, -0.2641));
+        stations.add(new Station("39", "Caledonian Road", 51.5481, -0.1188));
+        stations.add(new Station("40", "Camden Town", 51.5392, -0.1426));
+        stations.add(new Station("41", "Canada Water", 51.4982, -0.0502));
+        stations.add(new Station("42", "Canary Wharf", 51.5051, -0.0209));
+        stations.add(new Station("43", "Canning Town", 51.5147, 0.0082));
+        stations.add(new Station("44", "Cannon Street", 51.5113, -0.0904));
+        stations.add(new Station("45", "Canons Park", 51.6078, -0.2947));
+        stations.add(new Station("46", "Chalfont & Latimer", 51.6679, -0.561));
+        stations.add(new Station("47", "Chalk Farm", 51.5441, -0.1538));
+        stations.add(new Station("48", "Chancery Lane", 51.5185, -0.1111));
+        stations.add(new Station("49", "Charing Cross", 51.508, -0.1247));
+        stations.add(new Station("50", "Chesham", 51.7052, -0.611));
+        stations.add(new Station("51", "Chigwell", 51.6177, 0.0755));
+        stations.add(new Station("52", "Chiswick Park", 51.4946, -0.2678));
+        stations.add(new Station("53", "Chorleywood", 51.6543, -0.5183));
+        stations.add(new Station("54", "Clapham Common", 51.4618, -0.1384));
+        stations.add(new Station("55", "Clapham North", 51.4649, -0.1299));
+        stations.add(new Station("56", "Clapham South", 51.4527, -0.148));
+        stations.add(new Station("57", "Cockfosters", 51.6517, -0.1496));
+        stations.add(new Station("58", "Colindale", 51.5955, -0.2502));
+        stations.add(new Station("59", "Colliers Wood", 51.418, -0.1778));
+        stations.add(new Station("60", "Covent Garden", 51.5129, -0.1243));
+        stations.add(new Station("61", "Crossharbour & London Arena", 51.4957, -0.0144));
+        stations.add(new Station("62", "Croxley", 51.647, -0.4412));
+        stations.add(new Station("63", "Custom House", 51.5095, 0.0276));
+        stations.add(new Station("64", "Cutty Sark", 51.4827, -0.0096));
+        stations.add(new Station("65", "Cyprus", 51.5085, 0.064));
+        stations.add(new Station("66", "Dagenham East", 51.5443, 0.1655));
+        stations.add(new Station("67", "Dagenham Heathway", 51.5417, 0.1469));
+        stations.add(new Station("68", "Debden", 51.6455, 0.0838));
+        stations.add(new Station("69", "Deptford Bridge", 51.474, -0.0216));
+        stations.add(new Station("70", "Devons Road", 51.5223, -0.0173));
+        stations.add(new Station("71", "Dollis Hill", 51.552, -0.2387));
+        stations.add(new Station("72", "Ealing Broadway", 51.5152, -0.3017));
+        stations.add(new Station("73", "Ealing Common", 51.5101, -0.2882));
+        stations.add(new Station("74", "Earl's Court", 51.492, -0.1973));
+        stations.add(new Station("75", "Eastcote", 51.5765, -0.397));
+        stations.add(new Station("76", "East Acton", 51.5168, -0.2474));
+        stations.add(new Station("77", "East Finchley", 51.5874, -0.165));
+        stations.add(new Station("78", "East Ham", 51.5394, 0.0518));
+        stations.add(new Station("79", "East India", 51.5093, -0.0021));
+        stations.add(new Station("80", "East Putney", 51.4586, -0.2112));
+        stations.add(new Station("81", "Edgware", 51.6137, -0.275));
+        stations.add(new Station("82", "Edgware Road (B)", 51.5199, -0.1679));
+        stations.add(new Station("83", "Edgware Road (C)", 51.5203, -0.17));
+        stations.add(new Station("84", "Elephant & Castle", 51.4943, -0.1001));
+        stations.add(new Station("85", "Elm Park", 51.5496, 0.1977));
+        stations.add(new Station("86", "Elverson Road", 51.4693, -0.0174));
+        stations.add(new Station("87", "Embankment", 51.5074, -0.1223));
+        stations.add(new Station("88", "Epping", 51.6937, 0.1139));
+        stations.add(new Station("89", "Euston", 51.5282, -0.1337));
+        stations.add(new Station("90", "Euston Square", 51.526, -0.1359));
+        stations.add(new Station("91", "Fairlop", 51.596, 0.0912));
+        stations.add(new Station("92", "Farringdon", 51.5203, -0.1053));
+        stations.add(new Station("93", "Finchley Central", 51.6012, -0.1932));
+        stations.add(new Station("94", "Finchley Road", 51.5472, -0.1803));
+        stations.add(new Station("95", "Finsbury Park", 51.5642, -0.1065));
+        stations.add(new Station("96", "Fulham Broadway", 51.4804, -0.195));
+        stations.add(new Station("97", "Gallions Reach", 51.5096, 0.0716));
+        stations.add(new Station("98", "Gants Hill", 51.5765, 0.0663));
+        stations.add(new Station("99", "Gloucester Road", 51.4945, -0.1829));
+        stations.add(new Station("100", "Golders Green", 51.5724, -0.1941));
+        stations.add(new Station("101", "Goldhawk Road", 51.5018, -0.2267));
+        stations.add(new Station("102", "Goodge Street", 51.5205, -0.1347));
+        stations.add(new Station("103", "Grange Hill", 51.6132, 0.0923));
+        stations.add(new Station("104", "Great Portland Street", 51.5238, -0.1439));
+        stations.add(new Station("105", "Greenford", 51.5423, -0.3456));
+        stations.add(new Station("106", "Greenwich", 51.4781, -0.0149));
+        stations.add(new Station("107", "Green Park", 51.5067, -0.1428));
+        stations.add(new Station("108", "Gunnersbury", 51.4915, -0.2754));
+        stations.add(new Station("109", "Hainault", 51.603, 0.0933));
+        stations.add(new Station("110", "Hammersmith", 51.4936, -0.2251));
+        stations.add(new Station("111", "Hampstead", 51.5568, -0.178));
+        stations.add(new Station("112", "Hanger Lane", 51.5302, -0.2933));
+        stations.add(new Station("113", "Harlesden", 51.5362, -0.2575));
+        stations.add(new Station("114", "Harrow & Wealdston", 51.5925, -0.3351));
+        stations.add(new Station("115", "Harrow-on-the-Hill", 51.5793, -0.3366));
+        stations.add(new Station("116", "Hatton Cross", 51.4669, -0.4227));
+        stations.add(new Station("117", "Heathrow Terminals 1, 2 & 3", 51.4713, -0.4524));
+        stations.add(new Station("118", "Heathrow Terminal 4", 51.4598, -0.4476));
+        stations.add(new Station("119", "Hendon Central", 51.5829, -0.2259));
+        stations.add(new Station("120", "Heron Quays", 51.5033, -0.0215));
+        stations.add(new Station("121", "High Barnet", 51.6503, -0.1943));
+        stations.add(new Station("122", "High Street Kensington", 51.5009, -0.1925));
+        stations.add(new Station("123", "Highbury & Islington", 51.546, -0.104));
+        stations.add(new Station("124", "Highgate", 51.5777, -0.1458));
+        stations.add(new Station("125", "Hillingdon", 51.5538, -0.4499));
+        stations.add(new Station("126", "Holborn", 51.5174, -0.12));
+        stations.add(new Station("127", "Holland Park", 51.5075, -0.206));
+        stations.add(new Station("128", "Holloway Road", 51.5526, -0.1132));
+        stations.add(new Station("129", "Hornchurch", 51.5539, 0.2184));
+        stations.add(new Station("130", "Hounslow Central", 51.4713, -0.3665));
+        stations.add(new Station("131", "Hounslow East", 51.4733, -0.3564));
+        stations.add(new Station("132", "Hounslow West", 51.4734, -0.3855));
+        stations.add(new Station("133", "Hyde Park Corner", 51.5027, -0.1527));
+        stations.add(new Station("134", "Ickenham", 51.5619, -0.4421));
+        stations.add(new Station("135", "Island Gardens", 51.4871, -0.0101));
+        stations.add(new Station("136", "Kennington", 51.4884, -0.1053));
+        stations.add(new Station("137", "Kensal Green", 51.5304, -0.225));
+        stations.add(new Station("138", "Kensington (Olympia)", 51.4983, -0.2106));
+        stations.add(new Station("139", "Kentish Town", 51.5507, -0.1402));
+        stations.add(new Station("140", "Kenton", 51.5816, -0.3162));
+        stations.add(new Station("141", "Kew Gardens", 51.477, -0.285));
+        stations.add(new Station("142", "Kilburn", 51.5471, -0.2047));
+        stations.add(new Station("143", "Kilburn Park", 51.5351, -0.1939));
+        stations.add(new Station("144", "Kingsbury", 51.5846, -0.2786));
+        stations.add(new Station("145", "King's Cross St. Pancras", 51.5308, -0.1238));
+        stations.add(new Station("146", "Knightsbridge", 51.5015, -0.1607));
+        stations.add(new Station("147", "Ladbroke Grove", 51.5172, -0.2107));
+        stations.add(new Station("148", "Lambeth North", 51.4991, -0.1115));
+        stations.add(new Station("149", "Lancaster Gate", 51.5119, -0.1756));
+        stations.add(new Station("150", "Latimer Road", 51.5139, -0.2172));
+        stations.add(new Station("151", "Leicester Square", 51.5113, -0.1281));
+        stations.add(new Station("152", "Lewisham", 51.4657, -0.0142));
+        stations.add(new Station("153", "Leyton", 51.5566, -0.0053));
+        stations.add(new Station("154", "Leytonstone", 51.5683, 0.0083));
+        stations.add(new Station("155", "Limehouse", 51.5123, -0.0396));
+        stations.add(new Station("156", "Liverpool Street", 51.5178, -0.0823));
+        stations.add(new Station("157", "London Bridge", 51.5052, -0.0864));
+        stations.add(new Station("158", "Loughton", 51.6412, 0.0558));
+        stations.add(new Station("159", "Maida Vale", 51.53, -0.1854));
+        stations.add(new Station("160", "Manor House", 51.5712, -0.0958));
+        stations.add(new Station("161", "Mansion House", 51.5122, -0.094));
+        stations.add(new Station("162", "Marble Arch", 51.5136, -0.1586));
+        stations.add(new Station("163", "Marylebone", 51.5225, -0.1631));
+        stations.add(new Station("164", "Mile End", 51.5249, -0.0332));
+        stations.add(new Station("165", "Mill Hill East", 51.6082, -0.2103));
+        stations.add(new Station("166", "Monument", 51.5108, -0.0863));
+        stations.add(new Station("167", "Moorgate", 51.5186, -0.0886));
+        stations.add(new Station("168", "Moor Park", 51.6294, -0.432));
+        stations.add(new Station("169", "Morden", 51.4022, -0.1948));
+        stations.add(new Station("170", "Mornington Crescent", 51.5342, -0.1387));
+        stations.add(new Station("171", "Mudchute", 51.4902, -0.0145));
+        stations.add(new Station("172", "Neasden", 51.5542, -0.2503));
+        stations.add(new Station("173", "Newbury Park", 51.5756, 0.0899));
+        stations.add(new Station("174", "New Cross", 51.4767, -0.0327));
+        stations.add(new Station("175", "New Cross Gate", 51.4757, -0.0402));
+        stations.add(new Station("176", "Northfields", 51.4995, -0.3142));
+        stations.add(new Station("177", "Northolt", 51.5483, -0.3687));
+        stations.add(new Station("178", "Northwick Park", 51.5784, -0.3184));
+        stations.add(new Station("179", "Northwood", 51.6111, -0.424));
+        stations.add(new Station("180", "Northwood Hills", 51.6004, -0.4092));
+        stations.add(new Station("181", "North Acton", 51.5237, -0.2597));
+        stations.add(new Station("182", "North Ealing", 51.5175, -0.2887));
+        stations.add(new Station("183", "North Greenwich", 51.5005, 0.0039));
+        stations.add(new Station("184", "North Harrow", 51.5846, -0.3626));
+        stations.add(new Station("185", "North Wembley", 51.5621, -0.3034));
+        stations.add(new Station("186", "Notting Hill Gate", 51.5094, -0.1967));
+        stations.add(new Station("187", "Oakwood", 51.6476, -0.1318));
+        stations.add(new Station("188", "Old Street", 51.5263, -0.0873));
+        stations.add(new Station("189", "Osterley", 51.4813, -0.3522));
+        stations.add(new Station("190", "Oval", 51.4819, -0.113));
+        stations.add(new Station("191", "Oxford Circus", 51.515, -0.1415));
+        stations.add(new Station("192", "Paddington", 51.5154, -0.1755));
+        stations.add(new Station("193", "Park Royal", 51.527, -0.2841));
+        stations.add(new Station("194", "Parsons Green", 51.4753, -0.2011));
+        stations.add(new Station("195", "Perivale", 51.5366, -0.3232));
+        stations.add(new Station("196", "Picadilly Circus", 51.5098, -0.1342));
+        stations.add(new Station("197", "Pimlico", 51.4893, -0.1334));
+        stations.add(new Station("198", "Pinner", 51.5926, -0.3805));
+        stations.add(new Station("199", "Plaistow", 51.5313, 0.0172));
+        stations.add(new Station("200", "Poplar", 51.5077, -0.0173));
+        stations.add(new Station("201", "Preston Road", 51.572, -0.2954));
+        stations.add(new Station("202", "Prince Regent", 51.5093, 0.0336));
+        stations.add(new Station("203", "Pudding Mill Lane", 51.5343, -0.0139));
+        stations.add(new Station("204", "Putney Bridge", 51.4682, -0.2089));
+        stations.add(new Station("205", "Queen's Park", 51.5341, -0.2047));
+        stations.add(new Station("206", "Queensbury", 51.5942, -0.2861));
+        stations.add(new Station("207", "Queensway", 51.5107, -0.1877));
+        stations.add(new Station("208", "Ravenscourt Park", 51.4942, -0.2359));
+        stations.add(new Station("209", "Rayners Lane", 51.5753, -0.3714));
+        stations.add(new Station("210", "Redbridge", 51.5763, 0.0454));
+        stations.add(new Station("211", "Regent's Park", 51.5234, -0.1466));
+        stations.add(new Station("212", "Richmond", 51.4633, -0.3013));
+        stations.add(new Station("213", "Rickmansworth", 51.6404, -0.4733));
+        stations.add(new Station("214", "Roding Valley", 51.6171, 0.0439));
+        stations.add(new Station("215", "Rotherhithe", 51.501, -0.0525));
+        stations.add(new Station("216", "Royal Albert", 51.5084, 0.0465));
+        stations.add(new Station("217", "Royal Oak", 51.519, -0.188));
+        stations.add(new Station("218", "Royal Victoria", 51.5091, 0.0181));
+        stations.add(new Station("219", "Ruislip", 51.5715, -0.4213));
+        stations.add(new Station("220", "Ruislip Gardens", 51.5606, -0.4103));
+        stations.add(new Station("221", "Ruislip Manor", 51.5732, -0.4125));
+        stations.add(new Station("222", "Russell Square", 51.523, -0.1244));
+        stations.add(new Station("223", "Seven Sisters", 51.5822, -0.0749));
+        stations.add(new Station("224", "Shadwell", 51.5117, -0.056));
+        stations.add(new Station("225", "Shepherd's Bush (C)", 51.5046, -0.2187));
+        stations.add(new Station("226", "Shepherd's Bush (H)", 51.5058, -0.2265));
+        stations.add(new Station("227", "Shoreditch", 51.5227, -0.0708));
+        stations.add(new Station("228", "Sloane Square", 51.4924, -0.1565));
+        stations.add(new Station("229", "Snaresbrook", 51.5808, 0.0216));
+        stations.add(new Station("230", "Southfields", 51.4454, -0.2066));
+        stations.add(new Station("231", "Southgate", 51.6322, -0.128));
+        stations.add(new Station("232", "Southwark", 51.501, -0.1052));
+        stations.add(new Station("233", "South Ealing", 51.5011, -0.3072));
+        stations.add(new Station("234", "South Harrow", 51.5646, -0.3521));
+        stations.add(new Station("235", "South Kensington", 51.4941, -0.1738));
+        stations.add(new Station("236", "South Kenton", 51.5701, -0.3081));
+        stations.add(new Station("237", "South Quay", 51.5007, -0.0191));
+        stations.add(new Station("238", "South Ruislip", 51.5569, -0.3988));
+        stations.add(new Station("239", "South Wimbledon", 51.4154, -0.1919));
+        stations.add(new Station("240", "South Woodford", 51.5917, 0.0275));
+        stations.add(new Station("241", "Stamford Brook", 51.495, -0.2459));
+        stations.add(new Station("242", "Stanmore", 51.6194, -0.3028));
+        stations.add(new Station("243", "Stepney Green", 51.5221, -0.047));
+        stations.add(new Station("244", "Stockwell", 51.4723, -0.123));
+        stations.add(new Station("245", "Stonebridge Park", 51.5439, -0.2759));
+        stations.add(new Station("246", "Stratford", 51.5416, -0.0042));
+        stations.add(new Station("247", "St. James's Park", 51.4994, -0.1335));
+        stations.add(new Station("248", "St. John's Wood", 51.5347, -0.174));
+        stations.add(new Station("249", "St. Paul's", 51.5146, -0.0973));
+        stations.add(new Station("250", "Sudbury Hill", 51.5569, -0.3366));
+        stations.add(new Station("251", "Sudbury Town", 51.5507, -0.3156));
+        stations.add(new Station("252", "Surrey Quays", 51.4933, -0.0478));
+        stations.add(new Station("253", "Swiss Cottage", 51.5432, -0.1738));
+        stations.add(new Station("254", "Temple", 51.5111, -0.1141));
+        stations.add(new Station("255", "Theydon Bois", 51.6717, 0.1033));
+        stations.add(new Station("256", "Tooting Bec", 51.4361, -0.1598));
+        stations.add(new Station("257", "Tooting Broadway", 51.4275, -0.168));
+        stations.add(new Station("258", "Tottenham Court Road", 51.5165, -0.131));
+        stations.add(new Station("259", "Tottenham Hale", 51.5882, -0.0594));
+        stations.add(new Station("260", "Totteridge & Whetstone", 51.6302, -0.1791));
+        stations.add(new Station("261", "Tower Gateway", 51.5106, -0.0743));
+        stations.add(new Station("262", "Tower Hill", 51.5098, -0.0766));
+        stations.add(new Station("263", "Tufnell Park", 51.5567, -0.1374));
+        stations.add(new Station("264", "Turnham Green", 51.4951, -0.2547));
+        stations.add(new Station("265", "Turnpike Lane", 51.5904, -0.1028));
+        stations.add(new Station("266", "Upminster", 51.559, 0.251));
+        stations.add(new Station("267", "Upminster Bridge", 51.5582, 0.2343));
+        stations.add(new Station("268", "Upney", 51.5385, 0.1014));
+        stations.add(new Station("269", "Upton Park", 51.5352, 0.0343));
+        stations.add(new Station("270", "Uxbridge", 51.5463, -0.4786));
+        stations.add(new Station("271", "Vauxhall", 51.4861, -0.1253));
+        stations.add(new Station("272", "Victoria", 51.4965, -0.1447));
+        stations.add(new Station("273", "Walthamstow Central", 51.583, -0.0195));
+        stations.add(new Station("274", "Wanstead", 51.5775, 0.0288));
+        stations.add(new Station("275", "Wapping", 51.5043, -0.0558));
+        stations.add(new Station("276", "Warren Street", 51.5247, -0.1384));
+        stations.add(new Station("277", "Warwick Avenue", 51.5235, -0.1835));
+        stations.add(new Station("278", "Waterloo", 51.5036, -0.1143));
+        stations.add(new Station("279", "Watford", 51.6573, -0.4177));
+        stations.add(new Station("280", "Wembley Central", 51.5519, -0.2963));
+        stations.add(new Station("281", "Wembley Park", 51.5635, -0.2795));
+        stations.add(new Station("282", "Westbourne Park", 51.521, -0.2011));
+        stations.add(new Station("283", "Westferry", 51.5097, -0.0265));
+        stations.add(new Station("284", "Westminster", 51.501, -0.1254));
+        stations.add(new Station("285", "West Acton", 51.518, -0.2809));
+        stations.add(new Station("286", "West Brompton", 51.4872, -0.1953));
+        stations.add(new Station("287", "West Finchley", 51.6095, -0.1883));
+        stations.add(new Station("288", "West Ham", 51.5287, 0.0056));
+        stations.add(new Station("289", "West Hampstead", 51.5469, -0.1906));
+        stations.add(new Station("290", "West Harrow", 51.5795, -0.3533));
+        stations.add(new Station("291", "West India Quay", 51.507, -0.0203));
+        stations.add(new Station("292", "West Kensington", 51.4907, -0.2065));
+        stations.add(new Station("293", "West Ruislip", 51.5696, -0.4376));
+        stations.add(new Station("294", "Whitechapel", 51.5194, -0.0612));
+        stations.add(new Station("295", "White City", 51.512, -0.2239));
+        stations.add(new Station("296", "Willesden Green", 51.5492, -0.2215));
+        stations.add(new Station("297", "Willesden Junction", 51.5326, -0.2478));
+        stations.add(new Station("298", "Wimbledon", 51.4214, -0.2064));
+        stations.add(new Station("299", "Wimbledon Park", 51.4343, -0.1992));
+        stations.add(new Station("300", "Woodford", 51.607, 0.0341));
+        stations.add(new Station("301", "Woodside Park", 51.6179, -0.1856));
+        stations.add(new Station("302", "Wood Green", 51.5975, -0.1097));
+
+        connections.put("1", Stream.of("52","73","73","233","264").collect(Collectors.toSet()));
+        connections.put("2", Stream.of("156","262","156").collect(Collectors.toSet()));
+        connections.put("3", Stream.of("262","294","156","294").collect(Collectors.toSet()));
+        connections.put("4", Stream.of("70","200").collect(Collectors.toSet()));
+        connections.put("5", Stream.of("193","251").collect(Collectors.toSet()));
+        connections.put("6", Stream.of("46").collect(Collectors.toSet()));
+        connections.put("7", Stream.of("145","188").collect(Collectors.toSet()));
+        connections.put("8", Stream.of("124","263").collect(Collectors.toSet()));
+        connections.put("9", Stream.of("31","231").collect(Collectors.toSet()));
+        connections.put("10", Stream.of("95","128").collect(Collectors.toSet()));
+        connections.put("11", Stream.of("163","211","83","104","83","104","28","248","94","104").collect(Collectors.toSet()));
+        connections.put("12", Stream.of("56","256").collect(Collectors.toSet()));
+        connections.put("13", Stream.of("156","249","224","157","167","278").collect(Collectors.toSet()));
+        connections.put("14", Stream.of("92","167","92","167","92","167").collect(Collectors.toSet()));
+        connections.put("15", Stream.of("78","268","78").collect(Collectors.toSet()));
+        connections.put("16", Stream.of("91","173").collect(Collectors.toSet()));
+        connections.put("17", Stream.of("110","292","74","110").collect(Collectors.toSet()));
+        connections.put("18", Stream.of("186","192","186","192").collect(Collectors.toSet()));
+        connections.put("19", Stream.of("97").collect(Collectors.toSet()));
+        connections.put("20", Stream.of("65","216").collect(Collectors.toSet()));
+        connections.put("21", Stream.of("67","268").collect(Collectors.toSet()));
+        connections.put("22", Stream.of("47","111").collect(Collectors.toSet()));
+        connections.put("23", Stream.of("41","157").collect(Collectors.toSet()));
+        connections.put("24", Stream.of("156","164").collect(Collectors.toSet()));
+        connections.put("25", Stream.of("161","254","161","254").collect(Collectors.toSet()));
+        connections.put("26", Stream.of("259","273").collect(Collectors.toSet()));
+        connections.put("27", Stream.of("79","200").collect(Collectors.toSet()));
+        connections.put("28", Stream.of("162","191","11","107").collect(Collectors.toSet()));
+        connections.put("29", Stream.of("84","157").collect(Collectors.toSet()));
+        connections.put("30", Stream.of("176","189").collect(Collectors.toSet()));
+        connections.put("31", Stream.of("9","302").collect(Collectors.toSet()));
+        connections.put("32", Stream.of("70","203").collect(Collectors.toSet()));
+        connections.put("33", Stream.of("36","164","36","164").collect(Collectors.toSet()));
+        connections.put("34", Stream.of("100","119").collect(Collectors.toSet()));
+        connections.put("35", Stream.of("244").collect(Collectors.toSet()));
+        connections.put("36", Stream.of("33","288","33","288").collect(Collectors.toSet()));
+        connections.put("37", Stream.of("158","300").collect(Collectors.toSet()));
+        connections.put("38", Stream.of("58","81").collect(Collectors.toSet()));
+        connections.put("39", Stream.of("128","145").collect(Collectors.toSet()));
+        connections.put("40", Stream.of("47","89","139","170").collect(Collectors.toSet()));
+        connections.put("41", Stream.of("215","252","23","42").collect(Collectors.toSet()));
+        connections.put("42", Stream.of("120","291","41","183").collect(Collectors.toSet()));
+        connections.put("43", Stream.of("79","218","183","288").collect(Collectors.toSet()));
+        connections.put("44", Stream.of("161","166","161","166").collect(Collectors.toSet()));
+        connections.put("45", Stream.of("206","242").collect(Collectors.toSet()));
+        connections.put("46", Stream.of("6","50","53").collect(Collectors.toSet()));
+        connections.put("47", Stream.of("22","40").collect(Collectors.toSet()));
+        connections.put("48", Stream.of("126","249").collect(Collectors.toSet()));
+        connections.put("49", Stream.of("87","196","87","151").collect(Collectors.toSet()));
+        connections.put("50", Stream.of("46").collect(Collectors.toSet()));
+        connections.put("51", Stream.of("103","214").collect(Collectors.toSet()));
+        connections.put("52", Stream.of("1","264").collect(Collectors.toSet()));
+        connections.put("53", Stream.of("46","213").collect(Collectors.toSet()));
+        connections.put("54", Stream.of("55","56").collect(Collectors.toSet()));
+        connections.put("55", Stream.of("54","244").collect(Collectors.toSet()));
+        connections.put("56", Stream.of("12","54").collect(Collectors.toSet()));
+        connections.put("57", Stream.of("187").collect(Collectors.toSet()));
+        connections.put("58", Stream.of("38","119").collect(Collectors.toSet()));
+        connections.put("59", Stream.of("239","257").collect(Collectors.toSet()));
+        connections.put("60", Stream.of("126","151").collect(Collectors.toSet()));
+        connections.put("61", Stream.of("171","237").collect(Collectors.toSet()));
+        connections.put("62", Stream.of("168","279").collect(Collectors.toSet()));
+        connections.put("63", Stream.of("202","218").collect(Collectors.toSet()));
+        connections.put("64", Stream.of("106","135").collect(Collectors.toSet()));
+        connections.put("65", Stream.of("20","97").collect(Collectors.toSet()));
+        connections.put("66", Stream.of("67","85").collect(Collectors.toSet()));
+        connections.put("67", Stream.of("21","66").collect(Collectors.toSet()));
+        connections.put("68", Stream.of("158","255").collect(Collectors.toSet()));
+        connections.put("69", Stream.of("86","106").collect(Collectors.toSet()));
+        connections.put("70", Stream.of("4","32").collect(Collectors.toSet()));
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+        connections.put("72", Stream.of("285","73").collect(Collectors.toSet()));
+        connections.put("73", Stream.of("72","1","1","182").collect(Collectors.toSet()));
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+        connections.put("76", Stream.of("181","295").collect(Collectors.toSet()));
+        connections.put("77", Stream.of("93","124").collect(Collectors.toSet()));
+        connections.put("78", Stream.of("15","269","15","269").collect(Collectors.toSet()));
+        connections.put("79", Stream.of("27","43").collect(Collectors.toSet()));
+        connections.put("80", Stream.of("204","230").collect(Collectors.toSet()));
+        connections.put("81", Stream.of("38").collect(Collectors.toSet()));
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+        connections.put("84", Stream.of("148","29","136").collect(Collectors.toSet()));
+        connections.put("85", Stream.of("66","129").collect(Collectors.toSet()));
+        connections.put("86", Stream.of("69","152").collect(Collectors.toSet()));
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+        connections.put("88", Stream.of("255").collect(Collectors.toSet()));
+        connections.put("89", Stream.of("40","145","170","276","145","276").collect(Collectors.toSet()));
+        connections.put("90", Stream.of("104","145","104","145","104","145").collect(Collectors.toSet()));
+        connections.put("91", Stream.of("16","109").collect(Collectors.toSet()));
+        connections.put("92", Stream.of("14","145","14","145","14","145").collect(Collectors.toSet()));
+        connections.put("93", Stream.of("77","165","287").collect(Collectors.toSet()));
+        connections.put("94", Stream.of("253","289","11","281").collect(Collectors.toSet()));
+        connections.put("95", Stream.of("10","160","123","223").collect(Collectors.toSet()));
+        connections.put("96", Stream.of("194","286").collect(Collectors.toSet()));
+        connections.put("97", Stream.of("19","65").collect(Collectors.toSet()));
+        connections.put("98", Stream.of("173","210").collect(Collectors.toSet()));
+        connections.put("99", Stream.of("122","235","74","235","74","235").collect(Collectors.toSet()));
+        connections.put("100", Stream.of("34","111").collect(Collectors.toSet()));
+        connections.put("101", Stream.of("110","226").collect(Collectors.toSet()));
+        connections.put("102", Stream.of("258","276").collect(Collectors.toSet()));
+        connections.put("103", Stream.of("51","109").collect(Collectors.toSet()));
+        connections.put("104", Stream.of("11","90","11","90","11","90").collect(Collectors.toSet()));
+        connections.put("105", Stream.of("177","195").collect(Collectors.toSet()));
+        connections.put("106", Stream.of("64","69").collect(Collectors.toSet()));
+        connections.put("107", Stream.of("28","284","133","196","191","272").collect(Collectors.toSet()));
+        connections.put("108", Stream.of("141","264").collect(Collectors.toSet()));
+        connections.put("109", Stream.of("91","103").collect(Collectors.toSet()));
+        connections.put("110", Stream.of("17","208","101","17","264").collect(Collectors.toSet()));
+        connections.put("111", Stream.of("22","100").collect(Collectors.toSet()));
+        connections.put("112", Stream.of("181","195").collect(Collectors.toSet()));
+        connections.put("113", Stream.of("245","297").collect(Collectors.toSet()));
+        connections.put("114", Stream.of("140").collect(Collectors.toSet()));
+        connections.put("115", Stream.of("178","184","290").collect(Collectors.toSet()));
+        connections.put("116", Stream.of("117","118","132").collect(Collectors.toSet()));
+        connections.put("117", Stream.of("116","118").collect(Collectors.toSet()));
+        connections.put("118", Stream.of("116","117").collect(Collectors.toSet()));
+        connections.put("119", Stream.of("34","58").collect(Collectors.toSet()));
+        connections.put("120", Stream.of("42","237").collect(Collectors.toSet()));
+        connections.put("121", Stream.of("260").collect(Collectors.toSet()));
+        connections.put("122", Stream.of("99","186","74","186").collect(Collectors.toSet()));
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+        connections.put("124", Stream.of("8","77").collect(Collectors.toSet()));
+        connections.put("125", Stream.of("134","270","134","270").collect(Collectors.toSet()));
+        connections.put("126", Stream.of("48","258","60","222").collect(Collectors.toSet()));
+        connections.put("127", Stream.of("186","225").collect(Collectors.toSet()));
+        connections.put("128", Stream.of("10","39").collect(Collectors.toSet()));
+        connections.put("129", Stream.of("85","267").collect(Collectors.toSet()));
+        connections.put("130", Stream.of("131","132").collect(Collectors.toSet()));
+        connections.put("131", Stream.of("130","189").collect(Collectors.toSet()));
+        connections.put("132", Stream.of("116","130").collect(Collectors.toSet()));
+        connections.put("133", Stream.of("107","146").collect(Collectors.toSet()));
+        connections.put("134", Stream.of("125","219","125","219").collect(Collectors.toSet()));
+        connections.put("135", Stream.of("64","171").collect(Collectors.toSet()));
+        connections.put("136", Stream.of("84","190","278").collect(Collectors.toSet()));
+        connections.put("137", Stream.of("205","297").collect(Collectors.toSet()));
+        connections.put("138", Stream.of("74").collect(Collectors.toSet()));
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+        connections.put("145", Stream.of("90","92","90","92","90","92","7","89","39","222","89","123").collect(Collectors.toSet()));
+        connections.put("146", Stream.of("133","235").collect(Collectors.toSet()));
+        connections.put("147", Stream.of("150","282").collect(Collectors.toSet()));
+        connections.put("148", Stream.of("84","278").collect(Collectors.toSet()));
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+        connections.put("151", Stream.of("49","258","60","196").collect(Collectors.toSet()));
+        connections.put("152", Stream.of("86").collect(Collectors.toSet()));
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+        connections.put("154", Stream.of("153","229","274").collect(Collectors.toSet()));
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+        connections.put("156", Stream.of("13","24","2","167","3","167","2","167").collect(Collectors.toSet()));
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+        connections.put("254", Stream.of("25","87","25","87").collect(Collectors.toSet()));
+        connections.put("255", Stream.of("68","88").collect(Collectors.toSet()));
+        connections.put("256", Stream.of("12","257").collect(Collectors.toSet()));
+        connections.put("257", Stream.of("59","256").collect(Collectors.toSet()));
+        connections.put("258", Stream.of("126","191","102","151").collect(Collectors.toSet()));
+        connections.put("259", Stream.of("26","223").collect(Collectors.toSet()));
+        connections.put("260", Stream.of("121","301").collect(Collectors.toSet()));
+        connections.put("261", Stream.of("224").collect(Collectors.toSet()));
+        connections.put("262", Stream.of("2","166","3","166").collect(Collectors.toSet()));
+        connections.put("263", Stream.of("8","139").collect(Collectors.toSet()));
+        connections.put("264", Stream.of("52","108","241","1","110").collect(Collectors.toSet()));
+        connections.put("265", Stream.of("160","302").collect(Collectors.toSet()));
+        connections.put("266", Stream.of("267").collect(Collectors.toSet()));
+        connections.put("267", Stream.of("129","266").collect(Collectors.toSet()));
+        connections.put("268", Stream.of("15","21").collect(Collectors.toSet()));
+        connections.put("269", Stream.of("78","199","78","199").collect(Collectors.toSet()));
+        connections.put("270", Stream.of("125","125").collect(Collectors.toSet()));
+        connections.put("271", Stream.of("197","244").collect(Collectors.toSet()));
+        connections.put("272", Stream.of("228","247","228","247","107","197").collect(Collectors.toSet()));
+        connections.put("273", Stream.of("26").collect(Collectors.toSet()));
+        connections.put("274", Stream.of("154","210").collect(Collectors.toSet()));
+        connections.put("275", Stream.of("215","224").collect(Collectors.toSet()));
+        connections.put("276", Stream.of("89","102","89","191").collect(Collectors.toSet()));
+        connections.put("277", Stream.of("159","192").collect(Collectors.toSet()));
+        connections.put("278", Stream.of("87","148","232","284","87","136","13").collect(Collectors.toSet()));
+        connections.put("279", Stream.of("62").collect(Collectors.toSet()));
+        connections.put("280", Stream.of("185","245").collect(Collectors.toSet()));
+        connections.put("281", Stream.of("144","172","94","201").collect(Collectors.toSet()));
+        connections.put("282", Stream.of("147","217").collect(Collectors.toSet()));
+        connections.put("283", Stream.of("155","200","291").collect(Collectors.toSet()));
+        connections.put("284", Stream.of("87","247","87","247","107","278").collect(Collectors.toSet()));
+        connections.put("285", Stream.of("72","181").collect(Collectors.toSet()));
+        connections.put("286", Stream.of("74","96").collect(Collectors.toSet()));
+        connections.put("287", Stream.of("93","301").collect(Collectors.toSet()));
+        connections.put("288", Stream.of("36","199","36","199","43","246").collect(Collectors.toSet()));
+        connections.put("289", Stream.of("94","142").collect(Collectors.toSet()));
+        connections.put("290", Stream.of("115","209").collect(Collectors.toSet()));
+        connections.put("291", Stream.of("42","200","283").collect(Collectors.toSet()));
+        connections.put("292", Stream.of("17","74").collect(Collectors.toSet()));
+        connections.put("293", Stream.of("220").collect(Collectors.toSet()));
+        connections.put("294", Stream.of("3","243","224","227","3","243").collect(Collectors.toSet()));
+        connections.put("295", Stream.of("76","225").collect(Collectors.toSet()));
+        connections.put("296", Stream.of("71","142").collect(Collectors.toSet()));
+        connections.put("297", Stream.of("113","137").collect(Collectors.toSet()));
+        connections.put("298", Stream.of("299").collect(Collectors.toSet()));
+        connections.put("299", Stream.of("230","298").collect(Collectors.toSet()));
+        connections.put("300", Stream.of("37","214","240").collect(Collectors.toSet()));
+        connections.put("301", Stream.of("260","287").collect(Collectors.toSet()));
+        connections.put("302", Stream.of("31","265").collect(Collectors.toSet()));
+
+        underground = new Graph<>(stations, connections);
+        routeFinder = new RouteFinder<>(underground, new HaversineScorer(), new HaversineScorer());
+    }
+
+    @Test
+    public void findRoute() {
+        List<Station> route = routeFinder.findRoute(underground.getNode("74"), underground.getNode("7"));
+        assertThat(route).size().isPositive();
+
+        route.stream().map(Station::getName).collect(Collectors.toList()).forEach(station -> log.debug(station));
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/astar/underground/Station.java

@@ -0,0 +1,42 @@
+package com.baeldung.algorithms.astar.underground;
+
+import java.util.StringJoiner;
+
+import com.baeldung.algorithms.astar.GraphNode;
+
+public class Station implements GraphNode {
+    private final String id;
+    private final String name;
+    private final double latitude;
+    private final double longitude;
+
+    public Station(String id, String name, double latitude, double longitude) {
+        this.id = id;
+        this.name = name;
+        this.latitude = latitude;
+        this.longitude = longitude;
+    }
+
+    @Override
+    public String getId() {
+        return id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public double getLatitude() {
+        return latitude;
+    }
+
+    public double getLongitude() {
+        return longitude;
+    }
+
+    @Override
+    public String toString() {
+        return new StringJoiner(", ", Station.class.getSimpleName() + "[", "]").add("id='" + id + "'")
+            .add("name='" + name + "'").add("latitude=" + latitude).add("longitude=" + longitude).toString();
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/editdistance/EditDistanceDataProvider.java

@@ -0,0 +1,21 @@
+package com.baeldung.algorithms.editdistance;
+
+import org.junit.runners.Parameterized.Parameters;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+public class EditDistanceDataProvider {
+
+    @Parameters
+    public static Collection<Object[]> getLists() {
+        return Arrays.asList(new Object[][] { 
+            { "", "", 0 }, 
+            { "ago", "", 3 }, 
+            { "", "do", 2 }, 
+            { "abc", "adc", 1 }, 
+            { "peek", "pesek", 1 }, 
+            { "sunday", "saturday", 3 } 
+        });
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/editdistance/EditDistanceUnitTest.java

@@ -0,0 +1,32 @@
+package com.baeldung.algorithms.editdistance;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+import static org.junit.Assert.assertEquals;
+
+@RunWith(Parameterized.class)
+public class EditDistanceUnitTest extends EditDistanceDataProvider {
+
+    private String x;
+    private String y;
+    private int result;
+
+    public EditDistanceUnitTest(String a, String b, int res) {
+        super();
+        x = a;
+        y = b;
+        result = res;
+    }
+
+    @Test
+    public void testEditDistance_RecursiveImplementation() {
+        assertEquals(result, EditDistanceRecursive.calculate(x, y));
+    }
+
+    @Test
+    public void testEditDistance_givenDynamicProgrammingImplementation() {
+        assertEquals(result, EditDistanceDynamicProgramming.calculate(x, y));
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/linkedlist/CycleDetectionBruteForceUnitTest.java

@@ -0,0 +1,23 @@
+package com.baeldung.algorithms.linkedlist;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+@RunWith(value = Parameterized.class)
+public class CycleDetectionBruteForceUnitTest extends CycleDetectionTestBase {
+    boolean cycleExists;
+    Node<Integer> head;
+
+    public CycleDetectionBruteForceUnitTest(Node<Integer> head, boolean cycleExists) {
+        super();
+        this.cycleExists = cycleExists;
+        this.head = head;
+    }
+
+    @Test
+    public void givenList_detectLoop() {
+        Assert.assertEquals(cycleExists, CycleDetectionBruteForce.detectCycle(head).cycleExists);
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/linkedlist/CycleDetectionByFastAndSlowIteratorsUnitTest.java

@@ -0,0 +1,23 @@
+package com.baeldung.algorithms.linkedlist;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+@RunWith(value = Parameterized.class)
+public class CycleDetectionByFastAndSlowIteratorsUnitTest extends CycleDetectionTestBase {
+    boolean cycleExists;
+    Node<Integer> head;
+
+    public CycleDetectionByFastAndSlowIteratorsUnitTest(Node<Integer> head, boolean cycleExists) {
+        super();
+        this.cycleExists = cycleExists;
+        this.head = head;
+    }
+
+    @Test
+    public void givenList_detectLoop() {
+        Assert.assertEquals(cycleExists, CycleDetectionByFastAndSlowIterators.detectCycle(head).cycleExists);
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/linkedlist/CycleDetectionByHashingUnitTest.java

@@ -0,0 +1,23 @@
+package com.baeldung.algorithms.linkedlist;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+@RunWith(value = Parameterized.class)
+public class CycleDetectionByHashingUnitTest extends CycleDetectionTestBase {
+    boolean cycleExists;
+    Node<Integer> head;
+
+    public CycleDetectionByHashingUnitTest(Node<Integer> head, boolean cycleExists) {
+        super();
+        this.cycleExists = cycleExists;
+        this.head = head;
+    }
+
+    @Test
+    public void givenList_detectLoop() {
+        Assert.assertEquals(cycleExists, CycleDetectionByHashing.detectCycle(head).cycleExists);
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/linkedlist/CycleDetectionTestBase.java

@@ -0,0 +1,62 @@
+package com.baeldung.algorithms.linkedlist;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import org.junit.runners.Parameterized.Parameters;
+
+public class CycleDetectionTestBase {
+
+    @Parameters
+    public static Collection<Object[]> getLists() {
+        return Arrays.asList(new Object[][] { 
+            { createList(), false }, 
+            { createListWithLoop(), true },
+            { createListWithFullCycle(), true }, 
+            { createListWithSingleNodeInCycle(), true } 
+        });
+    }
+
+    public static Node<Integer> createList() {
+        Node<Integer> root = Node.createNewNode(10, null);
+
+        for (int i = 9; i >= 1; --i) {
+            Node<Integer> current = Node.createNewNode(i, root);
+            root = current;
+        }
+
+        return root;
+    }
+
+    public static Node<Integer> createListWithLoop() {
+        Node<Integer> node = createList();
+        createLoop(node);
+        return node;
+    }
+
+    public static Node<Integer> createListWithFullCycle() {
+        Node<Integer> head = createList();
+        Node<Integer> tail = Node.getTail(head);
+        tail.next = head;
+        return head;
+    }
+
+    public static Node<Integer> createListWithSingleNodeInCycle() {
+        Node<Integer> head = createList();
+        Node<Integer> tail = Node.getTail(head);
+        tail.next = tail;
+        return head;
+    }
+
+    public static void createLoop(Node<Integer> root) {
+        Node<Integer> tail = Node.getTail(root);
+
+        Node<Integer> middle = root;
+        for (int i = 1; i <= 4; i++) {
+            middle = middle.next;
+        }
+
+        tail.next = middle;
+    }
+
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/linkedlist/CycleRemovalBruteForceUnitTest.java

@@ -0,0 +1,24 @@
+package com.baeldung.algorithms.linkedlist;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+@RunWith(value = Parameterized.class)
+public class CycleRemovalBruteForceUnitTest extends CycleDetectionTestBase {
+    boolean cycleExists;
+    Node<Integer> head;
+
+    public CycleRemovalBruteForceUnitTest(Node<Integer> head, boolean cycleExists) {
+        super();
+        this.cycleExists = cycleExists;
+        this.head = head;
+    }
+
+    @Test
+    public void givenList_ifLoopExists_thenDetectAndRemoveLoop() {
+        Assert.assertEquals(cycleExists, CycleRemovalBruteForce.detectAndRemoveCycle(head));
+        Assert.assertFalse(CycleDetectionByFastAndSlowIterators.detectCycle(head).cycleExists);
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/linkedlist/CycleRemovalByCountingLoopNodesUnitTest.java

@@ -0,0 +1,24 @@
+package com.baeldung.algorithms.linkedlist;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+@RunWith(value = Parameterized.class)
+public class CycleRemovalByCountingLoopNodesUnitTest extends CycleDetectionTestBase {
+    boolean cycleExists;
+    Node<Integer> head;
+
+    public CycleRemovalByCountingLoopNodesUnitTest(Node<Integer> head, boolean cycleExists) {
+        super();
+        this.cycleExists = cycleExists;
+        this.head = head;
+    }
+
+    @Test
+    public void givenList_ifLoopExists_thenDetectAndRemoveLoop() {
+        Assert.assertEquals(cycleExists, CycleRemovalByCountingLoopNodes.detectAndRemoveCycle(head));
+        Assert.assertFalse(CycleDetectionByFastAndSlowIterators.detectCycle(head).cycleExists);
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/linkedlist/CycleRemovalWithoutCountingLoopNodesUnitTest.java

@@ -0,0 +1,24 @@
+package com.baeldung.algorithms.linkedlist;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+@RunWith(value = Parameterized.class)
+public class CycleRemovalWithoutCountingLoopNodesUnitTest extends CycleDetectionTestBase {
+    boolean cycleExists;
+    Node<Integer> head;
+
+    public CycleRemovalWithoutCountingLoopNodesUnitTest(Node<Integer> head, boolean cycleExists) {
+        super();
+        this.cycleExists = cycleExists;
+        this.head = head;
+    }
+
+    @Test
+    public void givenList_ifLoopExists_thenDetectAndRemoveLoop() {
+        Assert.assertEquals(cycleExists, CycleRemovalWithoutCountingLoopNodes.detectAndRemoveCycle(head));
+        Assert.assertFalse(CycleDetectionByFastAndSlowIterators.detectCycle(head).cycleExists);
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/algorithms/moneywords/NumberWordConverterUnitTest.java

@@ -0,0 +1,84 @@
+package com.baeldung.algorithms.moneywords;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+import com.baeldung.algorithms.numberwordconverter.NumberWordConverter;
+
+public class NumberWordConverterUnitTest {
+
+    @Test
+    public void whenMoneyNegative_thenReturnInvalidInput() {
+        assertEquals(NumberWordConverter.INVALID_INPUT_GIVEN, NumberWordConverter.getMoneyIntoWords(-13));
+    }
+
+    @Test
+    public void whenZeroDollarsGiven_thenReturnEmptyString() {
+        assertEquals("", NumberWordConverter.getMoneyIntoWords(0));
+    }
+
+    @Test
+    public void whenOnlyDollarsGiven_thenReturnWords() {
+        assertEquals("one dollar", NumberWordConverter.getMoneyIntoWords(1));
+    }
+
+    @Test
+    public void whenOnlyCentsGiven_thenReturnWords() {
+        assertEquals("sixty cents", NumberWordConverter.getMoneyIntoWords(0.6));
+    }
+    
+    @Test
+    public void whenAlmostAMillioDollarsGiven_thenReturnWords() {
+        String expectedResult = "nine hundred ninety nine thousand nine hundred ninety nine dollars";
+        assertEquals(expectedResult, NumberWordConverter.getMoneyIntoWords(999_999));
+    }
+    
+    @Test
+    public void whenThirtyMillionDollarsGiven_thenReturnWords() {
+        String expectedResult = "thirty three million three hundred forty eight thousand nine hundred seventy eight dollars";
+        assertEquals(expectedResult, NumberWordConverter.getMoneyIntoWords(33_348_978));
+    }
+    
+    @Test
+    public void whenTwoBillionDollarsGiven_thenReturnWords() {
+        String expectedResult = "two billion one hundred thirty three million two hundred forty seven thousand eight hundred ten dollars";
+        assertEquals(expectedResult, NumberWordConverter.getMoneyIntoWords(2_133_247_810));
+    }
+
+    @Test
+    public void whenGivenDollarsAndCents_thenReturnWords() {
+        String expectedResult = "nine hundred twenty four dollars and sixty cents";
+        assertEquals(expectedResult, NumberWordConverter.getMoneyIntoWords(924.6));
+    }
+
+    @Test
+    public void whenOneDollarAndNoCents_thenReturnDollarSingular() {
+        assertEquals("one dollar", NumberWordConverter.getMoneyIntoWords(1));
+    }
+
+    @Test
+    public void whenNoDollarsAndOneCent_thenReturnCentSingular() {
+        assertEquals("one cent", NumberWordConverter.getMoneyIntoWords(0.01));
+    }
+
+    @Test
+    public void whenNoDollarsAndTwoCents_thenReturnCentsPlural() {
+        assertEquals("two cents", NumberWordConverter.getMoneyIntoWords(0.02));
+    }
+
+    @Test
+    public void whenNoDollarsAndNinetyNineCents_thenReturnWords() {
+        assertEquals("ninety nine cents", NumberWordConverter.getMoneyIntoWords(0.99));
+    }
+
+    @Test
+    public void whenNoDollarsAndNineFiveNineCents_thenCorrectRounding() {
+        assertEquals("ninety six cents", NumberWordConverter.getMoneyIntoWords(0.959));
+    }
+
+    @Test
+    public void whenGivenDollarsAndCents_thenReturnWordsVersionTwo() {
+        assertEquals("three hundred ten £ 00/100", NumberWordConverter.getMoneyIntoWords("310"));
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/jgrapht/CompleteGraphUnitTest.java

@@ -0,0 +1,38 @@
+package com.baeldung.jgrapht;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.List;
+
+import org.jgrapht.VertexFactory;
+import org.jgrapht.alg.HamiltonianCycle;
+import org.jgrapht.generate.CompleteGraphGenerator;
+import org.jgrapht.graph.DefaultEdge;
+import org.jgrapht.graph.SimpleWeightedGraph;
+import org.junit.Before;
+import org.junit.Test;
+
+public class CompleteGraphUnitTest {
+
+    static SimpleWeightedGraph<String, DefaultEdge> completeGraph;
+    static int size = 10;
+
+    @Before
+    public void createCompleteGraph() {
+        completeGraph = new SimpleWeightedGraph<>(DefaultEdge.class);
+        CompleteGraphGenerator<String, DefaultEdge> completeGenerator = new CompleteGraphGenerator<String, DefaultEdge>(size);
+        VertexFactory<String> vFactory = new VertexFactory<String>() {
+            private int id = 0;
+            public String createVertex() {
+                return "v" + id++;
+            }
+        };
+        completeGenerator.generateGraph(completeGraph, vFactory, null);
+    }
+
+    @Test
+    public void givenCompleteGraph_whenGetHamiltonianCyclePath_thenGetVerticeListInSequence() {
+        List<String> verticeList = HamiltonianCycle.getApproximateOptimalForCompleteGraph(completeGraph);
+        assertEquals(verticeList.size(), completeGraph.vertexSet().size());
+    }
+}

algorithms-modules/algorithms-miscellaneous-2/src/test/java/com/baeldung/jgrapht/DirectedGraphUnitTest.java

@@ -0,0 +1,95 @@
+package com.baeldung.jgrapht;
+
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.IntStream;
+
+import org.jgrapht.DirectedGraph;
+import org.jgrapht.GraphPath;
+import org.jgrapht.alg.CycleDetector;
+import org.jgrapht.alg.KosarajuStrongConnectivityInspector;
+import org.jgrapht.alg.interfaces.StrongConnectivityAlgorithm;
+import org.jgrapht.alg.shortestpath.AllDirectedPaths;
+import org.jgrapht.alg.shortestpath.BellmanFordShortestPath;
+import org.jgrapht.alg.shortestpath.DijkstraShortestPath;
+import org.jgrapht.graph.DefaultDirectedGraph;
+import org.jgrapht.graph.DefaultEdge;
+import org.jgrapht.graph.DirectedSubgraph;
+import org.jgrapht.traverse.BreadthFirstIterator;
+import org.jgrapht.traverse.DepthFirstIterator;
+import org.junit.Before;
+import org.junit.Test;
+
+public class DirectedGraphUnitTest {
+    DirectedGraph<String, DefaultEdge> directedGraph;
+
+    @Before
+    public void createDirectedGraph() {
+        directedGraph = new DefaultDirectedGraph<String, DefaultEdge>(DefaultEdge.class);
+        IntStream.range(1, 10).forEach(i -> {
+            directedGraph.addVertex("v" + i);
+        });
+        directedGraph.addEdge("v1", "v2");
+        directedGraph.addEdge("v2", "v4");
+        directedGraph.addEdge("v4", "v3");
+        directedGraph.addEdge("v3", "v1");
+        directedGraph.addEdge("v5", "v4");
+        directedGraph.addEdge("v5", "v6");
+        directedGraph.addEdge("v6", "v7");
+        directedGraph.addEdge("v7", "v5");
+        directedGraph.addEdge("v8", "v5");
+        directedGraph.addEdge("v9", "v8");
+    }
+
+    @Test
+    public void givenDirectedGraph_whenGetStronglyConnectedSubgraphs_thenPathExistsBetweenStronglyconnectedVertices() {
+        StrongConnectivityAlgorithm<String, DefaultEdge> scAlg = new KosarajuStrongConnectivityInspector<>(directedGraph);
+        List<DirectedSubgraph<String, DefaultEdge>> stronglyConnectedSubgraphs = scAlg.stronglyConnectedSubgraphs();
+        List<String> stronglyConnectedVertices = new ArrayList<>(stronglyConnectedSubgraphs.get(3).vertexSet());
+
+        String randomVertex1 = stronglyConnectedVertices.get(0);
+        String randomVertex2 = stronglyConnectedVertices.get(3);
+        AllDirectedPaths<String, DefaultEdge> allDirectedPaths = new AllDirectedPaths<>(directedGraph);
+
+        List<GraphPath<String, DefaultEdge>> possiblePathList = allDirectedPaths.getAllPaths(randomVertex1, randomVertex2, false, stronglyConnectedVertices.size());
+        assertTrue(possiblePathList.size() > 0);
+    }
+
+    @Test
+    public void givenDirectedGraphWithCycle_whenCheckCycles_thenDetectCycles() {
+        CycleDetector<String, DefaultEdge> cycleDetector = new CycleDetector<String, DefaultEdge>(directedGraph);
+        assertTrue(cycleDetector.detectCycles());
+        Set<String> cycleVertices = cycleDetector.findCycles();
+        assertTrue(cycleVertices.size() > 0);
+    }
+
+    @Test
+    public void givenDirectedGraph_whenCreateInstanceDepthFirstIterator_thenGetIterator() {
+        DepthFirstIterator depthFirstIterator = new DepthFirstIterator<>(directedGraph);
+        assertNotNull(depthFirstIterator);
+    }
+
+    @Test
+    public void givenDirectedGraph_whenCreateInstanceBreadthFirstIterator_thenGetIterator() {
+        BreadthFirstIterator breadthFirstIterator = new BreadthFirstIterator<>(directedGraph);
+        assertNotNull(breadthFirstIterator);
+    }
+
+    @Test
+    public void givenDirectedGraph_whenGetDijkstraShortestPath_thenGetNotNullPath() {
+        DijkstraShortestPath dijkstraShortestPath = new DijkstraShortestPath(directedGraph);
+        List<String> shortestPath = dijkstraShortestPath.getPath("v1", "v4").getVertexList();
+        assertNotNull(shortestPath);
+    }
+
+    @Test
+    public void givenDirectedGraph_whenGetBellmanFordShortestPath_thenGetNotNullPath() {
+        BellmanFordShortestPath bellmanFordShortestPath = new BellmanFordShortestPath(directedGraph);
+        List<String> shortestPath = bellmanFordShortestPath.getPath("v1", "v4").getVertexList();
+        assertNotNull(shortestPath);
+    }
+}