[BAEL-19135] - Move search articles to a new module

2019-11-19 17:58:32 +02:00
parent dd4aae6139
commit 5e7d875d0f
31 changed files with 744 additions and 327 deletions
--- a/algorithms-searching/README.md
+++ b/algorithms-searching/README.md
@@ -0,0 +1,11 @@
+## Algorithms - Searching
+
+This module contains articles about searching algorithms.
+
+### Relevant articles:
+- [Binary Search Algorithm in Java](https://www.baeldung.com/java-binary-search)
+- [Depth First Search in Java](https://www.baeldung.com/java-depth-first-search)
+- [Interpolation Search in Java](https://www.baeldung.com/java-interpolation-search)
+- [Breadth-First Search Algorithm in Java](https://www.baeldung.com/java-breadth-first-search)
+- [String Search Algorithms for Large Texts](https://www.baeldung.com/java-full-text-search-algorithms)
+- [Monte Carlo Tree Search for Tic-Tac-Toe Game](https://www.baeldung.com/java-monte-carlo-tree-search)
--- a/algorithms-searching/pom.xml
+++ b/algorithms-searching/pom.xml
@@ -0,0 +1,37 @@
+<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-searching</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>algorithms-searching</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${org.assertj.core.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>algorithms-searching</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+    </build>
+
+    <properties>
+        <org.assertj.core.version>3.9.0</org.assertj.core.version>
+    </properties>
+
+</project>
--- a/algorithms-searching/src/main/java/com/baeldung/algorithms/binarysearch/BinarySearch.java
+++ b/algorithms-searching/src/main/java/com/baeldung/algorithms/binarysearch/BinarySearch.java
@@ -0,0 +1,55 @@
+package com.baeldung.algorithms.binarysearch;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+public class BinarySearch {
+
+    public int runBinarySearchIteratively(int[] sortedArray, int key, int low, int high) {
+
+        int index = Integer.MAX_VALUE;
+
+        while (low <= high) {
+
+            int mid = (low + high) / 2;
+
+            if (sortedArray[mid] < key) {
+                low = mid + 1;
+            } else if (sortedArray[mid] > key) {
+                high = mid - 1;
+            } else if (sortedArray[mid] == key) {
+                index = mid;
+                break;
+            }
+        }
+        return index;
+    }
+
+    public int runBinarySearchRecursively(int[] sortedArray, int key, int low, int high) {
+
+        int middle = (low + high) / 2;
+        if (high < low) {
+            return -1;
+        }
+
+        if (key == sortedArray[middle]) {
+          return middle;
+        } else if (key < sortedArray[middle]) {
+          return runBinarySearchRecursively(sortedArray, key, low, middle - 1);
+        } else {
+          return runBinarySearchRecursively(sortedArray, key, middle + 1, high);
+        }
+    }
+
+    public int runBinarySearchUsingJavaArrays(int[] sortedArray, Integer key) {
+        int index = Arrays.binarySearch(sortedArray, key);
+        return index;
+    }
+
+    public int runBinarySearchUsingJavaCollections(List<Integer> sortedList, Integer key) {
+        int index = Collections.binarySearch(sortedList, key);
+        return index;
+    }
+
+}
--- a/algorithms-searching/src/main/java/com/baeldung/algorithms/breadthfirstsearch/BreadthFirstSearchAlgorithm.java
+++ b/algorithms-searching/src/main/java/com/baeldung/algorithms/breadthfirstsearch/BreadthFirstSearchAlgorithm.java
@@ -0,0 +1,54 @@
+package com.baeldung.algorithms.breadthfirstsearch;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.*;
+
+public class BreadthFirstSearchAlgorithm {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(BreadthFirstSearchAlgorithm.class);
+
+    public static <T> Optional<Tree<T>> search(T value, Tree<T> root) {
+        Queue<Tree<T>> queue = new ArrayDeque<>();
+        queue.add(root);
+
+        Tree<T> currentNode;
+        while (!queue.isEmpty()) {
+            currentNode = queue.remove();
+            LOGGER.info("Visited node with value: {}", currentNode.getValue());
+
+            if (currentNode.getValue().equals(value)) {
+                return Optional.of(currentNode);
+            } else {
+                queue.addAll(currentNode.getChildren());
+            }
+        }
+
+        return Optional.empty();
+    }
+
+    public static <T> Optional<Node<T>> search(T value, Node<T> start) {
+        Queue<Node<T>> queue = new ArrayDeque<>();
+        queue.add(start);
+
+        Node<T> currentNode;
+        Set<Node<T>> alreadyVisited = new HashSet<>();
+
+        while (!queue.isEmpty()) {
+            currentNode = queue.remove();
+            LOGGER.info("Visited node with value: {}", currentNode.getValue());
+
+            if (currentNode.getValue().equals(value)) {
+                return Optional.of(currentNode);
+            } else {
+                alreadyVisited.add(currentNode);
+                queue.addAll(currentNode.getNeighbors());
+                queue.removeAll(alreadyVisited);
+            }
+        }
+
+        return Optional.empty();
+    }
+
+}
--- a/algorithms-searching/src/main/java/com/baeldung/algorithms/breadthfirstsearch/Node.java
+++ b/algorithms-searching/src/main/java/com/baeldung/algorithms/breadthfirstsearch/Node.java
@@ -0,0 +1,31 @@
+package com.baeldung.algorithms.breadthfirstsearch;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+public class Node<T> {
+
+    private T value;
+    private Set<Node<T>> neighbors;
+
+    public Node(T value) {
+        this.value = value;
+        this.neighbors = new HashSet<>();
+    }
+
+    public T getValue() {
+        return value;
+    }
+
+    public Set<Node<T>> getNeighbors() {
+        return Collections.unmodifiableSet(neighbors);
+    }
+
+    public void connect(Node<T> node) {
+        if (this == node) throw new IllegalArgumentException("Can't connect node to itself");
+        this.neighbors.add(node);
+        node.neighbors.add(this);
+    }
+
+}
--- a/algorithms-searching/src/main/java/com/baeldung/algorithms/breadthfirstsearch/Tree.java
+++ b/algorithms-searching/src/main/java/com/baeldung/algorithms/breadthfirstsearch/Tree.java
@@ -0,0 +1,34 @@
+package com.baeldung.algorithms.breadthfirstsearch;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class Tree<T> {
+
+    private T value;
+    private List<Tree<T>> children;
+
+    private Tree(T value) {
+        this.value = value;
+        this.children = new ArrayList<>();
+    }
+
+    public static <T> Tree<T> of(T value) {
+        return new Tree<>(value);
+    }
+
+    public T getValue() {
+        return value;
+    }
+
+    public List<Tree<T>> getChildren() {
+        return Collections.unmodifiableList(children);
+    }
+
+    public Tree<T> addChild(T value) {
+        Tree<T> newChild = new Tree<>(value);
+        children.add(newChild);
+        return newChild;
+    }
+}
--- a/algorithms-searching/src/main/java/com/baeldung/algorithms/dfs/BinaryTree.java
+++ b/algorithms-searching/src/main/java/com/baeldung/algorithms/dfs/BinaryTree.java
@@ -0,0 +1,227 @@
+package com.baeldung.algorithms.dfs;
+
+import java.util.LinkedList;
+import java.util.Queue;
+import java.util.Stack;
+
+public class BinaryTree {
+
+    Node root;
+
+    public void add(int value) {
+        root = addRecursive(root, value);
+    }
+
+    private Node addRecursive(Node current, int value) {
+
+        if (current == null) {
+            return new Node(value);
+        }
+
+        if (value < current.value) {
+            current.left = addRecursive(current.left, value);
+        } else if (value > current.value) {
+            current.right = addRecursive(current.right, value);
+        }
+
+        return current;
+    }
+
+    public boolean isEmpty() {
+        return root == null;
+    }
+
+    public int getSize() {
+        return getSizeRecursive(root);
+    }
+
+    private int getSizeRecursive(Node current) {
+        return current == null ? 0 : getSizeRecursive(current.left) + 1 + getSizeRecursive(current.right);
+    }
+
+    public boolean containsNode(int value) {
+        return containsNodeRecursive(root, value);
+    }
+
+    private boolean containsNodeRecursive(Node current, int value) {
+        if (current == null) {
+            return false;
+        }
+
+        if (value == current.value) {
+            return true;
+        }
+
+        return value < current.value
+          ? containsNodeRecursive(current.left, value)
+          : containsNodeRecursive(current.right, value);
+    }
+
+    public void delete(int value) {
+        root = deleteRecursive(root, value);
+    }
+
+    private Node deleteRecursive(Node current, int value) {
+        if (current == null) {
+            return null;
+        }
+
+        if (value == current.value) {
+            // Case 1: no children
+            if (current.left == null && current.right == null) {
+                return null;
+            }
+
+            // Case 2: only 1 child
+            if (current.right == null) {
+                return current.left;
+            }
+
+            if (current.left == null) {
+                return current.right;
+            }
+
+            // Case 3: 2 children
+            int smallestValue = findSmallestValue(current.right);
+            current.value = smallestValue;
+            current.right = deleteRecursive(current.right, smallestValue);
+            return current;
+        }
+        if (value < current.value) {
+            current.left = deleteRecursive(current.left, value);
+            return current;
+        }
+
+        current.right = deleteRecursive(current.right, value);
+        return current;
+    }
+
+    private int findSmallestValue(Node root) {
+        return root.left == null ? root.value : findSmallestValue(root.left);
+    }
+
+    public void traverseInOrder(Node node) {
+        if (node != null) {
+            traverseInOrder(node.left);
+            visit(node.value);
+            traverseInOrder(node.right);
+        }
+    }
+
+    public void traversePreOrder(Node node) {
+        if (node != null) {
+            visit(node.value);
+            traversePreOrder(node.left);
+            traversePreOrder(node.right);
+        }
+    }
+
+    public void traversePostOrder(Node node) {
+        if (node != null) {
+            traversePostOrder(node.left);
+            traversePostOrder(node.right);
+            visit(node.value);
+        }
+    }
+
+    public void traverseLevelOrder() {
+        if (root == null) {
+            return;
+        }
+
+        Queue<Node> nodes = new LinkedList<>();
+        nodes.add(root);
+
+        while (!nodes.isEmpty()) {
+
+            Node node = nodes.remove();
+
+            System.out.print(" " + node.value);
+
+            if (node.left != null) {
+                nodes.add(node.left);
+            }
+
+            if (node.left != null) {
+                nodes.add(node.right);
+            }
+        }
+    }
+
+    
+    public void traverseInOrderWithoutRecursion() {
+        Stack<Node> stack = new Stack<Node>();
+        Node current = root;
+        stack.push(root);
+        while(! stack.isEmpty()) {
+            while(current.left != null) {
+                current = current.left;                
+                stack.push(current);                
+            }
+            current = stack.pop();
+            visit(current.value);
+            if(current.right != null) {
+                current = current.right;                
+                stack.push(current);
+            }
+        }
+    }
+    
+    public void traversePreOrderWithoutRecursion() {
+        Stack<Node> stack = new Stack<Node>();
+        Node current = root;
+        stack.push(root);
+        while(! stack.isEmpty()) {
+            current = stack.pop();
+            visit(current.value);
+            
+            if(current.right != null)
+                stack.push(current.right);
+                
+            if(current.left != null)
+                stack.push(current.left);
+        }        
+    }
+    
+    public void traversePostOrderWithoutRecursion() {
+        Stack<Node> stack = new Stack<Node>();
+        Node prev = root;
+        Node current = root;
+        stack.push(root);
+
+        while (!stack.isEmpty()) {
+            current = stack.peek();
+            boolean hasChild = (current.left != null || current.right != null);
+            boolean isPrevLastChild = (prev == current.right || (prev == current.left && current.right == null));
+
+            if (!hasChild || isPrevLastChild) {
+                current = stack.pop();
+                visit(current.value);
+                prev = current;
+            } else {
+                if (current.right != null) {
+                    stack.push(current.right);
+                }
+                if (current.left != null) {
+                    stack.push(current.left);
+                }
+            }
+        }   
+    }    
+    
+    private void visit(int value) {
+        System.out.print(" " + value);        
+    }
+    
+    class Node {
+        int value;
+        Node left;
+        Node right;
+
+        Node(int value) {
+            this.value = value;
+            right = null;
+            left = null;
+        }
+    }
+}
--- a/algorithms-searching/src/main/java/com/baeldung/algorithms/dfs/Graph.java
+++ b/algorithms-searching/src/main/java/com/baeldung/algorithms/dfs/Graph.java
@@ -0,0 +1,74 @@
+package com.baeldung.algorithms.dfs;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.Stack;
+
+public class Graph {
+
+    private Map<Integer, List<Integer>> adjVertices;
+
+    public Graph() {
+        this.adjVertices = new HashMap<Integer, List<Integer>>();
+    }
+
+    public void addVertex(int vertex) {
+        adjVertices.putIfAbsent(vertex, new ArrayList<>());
+    }
+
+    public void addEdge(int src, int dest) {
+        adjVertices.get(src).add(dest);
+    }
+
+    public void dfsWithoutRecursion(int start) {
+        Stack<Integer> stack = new Stack<Integer>();
+        boolean[] isVisited = new boolean[adjVertices.size()];
+        stack.push(start);
+        while (!stack.isEmpty()) {
+            int current = stack.pop();
+            isVisited[current] = true;
+            visit(current);
+            for (int dest : adjVertices.get(current)) {
+                if (!isVisited[dest])
+                    stack.push(dest);
+            }
+        }
+    }
+
+    public void dfs(int start) {
+        boolean[] isVisited = new boolean[adjVertices.size()];
+        dfsRecursive(start, isVisited);
+    }
+
+    private void dfsRecursive(int current, boolean[] isVisited) {
+        isVisited[current] = true;
+        visit(current);
+        for (int dest : adjVertices.get(current)) {
+            if (!isVisited[dest])
+                dfsRecursive(dest, isVisited);
+        }
+    }
+
+    public List<Integer> topologicalSort(int start) {
+        LinkedList<Integer> result = new LinkedList<Integer>();
+        boolean[] isVisited = new boolean[adjVertices.size()];
+        topologicalSortRecursive(start, isVisited, result);
+        return result;
+    }
+
+    private void topologicalSortRecursive(int current, boolean[] isVisited, LinkedList<Integer> result) {
+        isVisited[current] = true;
+        for (int dest : adjVertices.get(current)) {
+            if (!isVisited[dest])
+                topologicalSortRecursive(dest, isVisited, result);
+        }
+        result.addFirst(current);
+    }
+
+    private void visit(int value) {
+        System.out.print(" " + value);        
+    }
+}
--- a/algorithms-searching/src/main/java/com/baeldung/algorithms/interpolationsearch/InterpolationSearch.java
+++ b/algorithms-searching/src/main/java/com/baeldung/algorithms/interpolationsearch/InterpolationSearch.java
@@ -0,0 +1,35 @@
+package com.baeldung.algorithms.interpolationsearch;
+
+public class InterpolationSearch {
+
+    public static int interpolationSearch(int[] data, int item) {
+
+        int highEnd = (data.length - 1);
+        int lowEnd = 0;
+
+        while (item >= data[lowEnd] && item <= data[highEnd] && lowEnd <= highEnd) {
+
+            int probe = lowEnd + (highEnd - lowEnd) * (item - data[lowEnd]) / (data[highEnd] - data[lowEnd]);
+
+            if (highEnd == lowEnd) {
+                if (data[lowEnd] == item) {
+                    return lowEnd;
+                } else {
+                    return -1;
+                }
+            }
+
+            if (data[probe] == item) {
+                return probe;
+            }
+
+            if (data[probe] < item) {
+                lowEnd = probe + 1;
+            } else {
+                highEnd = probe - 1;
+            }
+        }
+        return -1;
+    }
+
+}
--- a/algorithms-searching/src/main/java/com/baeldung/algorithms/mcts/montecarlo/MonteCarloTreeSearch.java
+++ b/algorithms-searching/src/main/java/com/baeldung/algorithms/mcts/montecarlo/MonteCarloTreeSearch.java
@@ -0,0 +1,109 @@
+package com.baeldung.algorithms.mcts.montecarlo;
+
+import java.util.List;
+
+import com.baeldung.algorithms.mcts.tictactoe.Board;
+import com.baeldung.algorithms.mcts.tree.Node;
+import com.baeldung.algorithms.mcts.tree.Tree;
+
+public class MonteCarloTreeSearch {
+
+    private static final int WIN_SCORE = 10;
+    private int level;
+    private int opponent;
+
+    public MonteCarloTreeSearch() {
+        this.level = 3;
+    }
+
+    public int getLevel() {
+        return level;
+    }
+
+    public void setLevel(int level) {
+        this.level = level;
+    }
+
+    private int getMillisForCurrentLevel() {
+        return 2 * (this.level - 1) + 1;
+    }
+
+    public Board findNextMove(Board board, int playerNo) {
+        long start = System.currentTimeMillis();
+        long end = start + 60 * getMillisForCurrentLevel();
+
+        opponent = 3 - playerNo;
+        Tree tree = new Tree();
+        Node rootNode = tree.getRoot();
+        rootNode.getState().setBoard(board);
+        rootNode.getState().setPlayerNo(opponent);
+
+        while (System.currentTimeMillis() < end) {
+            // Phase 1 - Selection
+            Node promisingNode = selectPromisingNode(rootNode);
+            // Phase 2 - Expansion
+            if (promisingNode.getState().getBoard().checkStatus() == Board.IN_PROGRESS)
+                expandNode(promisingNode);
+
+            // Phase 3 - Simulation
+            Node nodeToExplore = promisingNode;
+            if (promisingNode.getChildArray().size() > 0) {
+                nodeToExplore = promisingNode.getRandomChildNode();
+            }
+            int playoutResult = simulateRandomPlayout(nodeToExplore);
+            // Phase 4 - Update
+            backPropogation(nodeToExplore, playoutResult);
+        }
+
+        Node winnerNode = rootNode.getChildWithMaxScore();
+        tree.setRoot(winnerNode);
+        return winnerNode.getState().getBoard();
+    }
+
+    private Node selectPromisingNode(Node rootNode) {
+        Node node = rootNode;
+        while (node.getChildArray().size() != 0) {
+            node = UCT.findBestNodeWithUCT(node);
+        }
+        return node;
+    }
+
+    private void expandNode(Node node) {
+        List<State> possibleStates = node.getState().getAllPossibleStates();
+        possibleStates.forEach(state -> {
+            Node newNode = new Node(state);
+            newNode.setParent(node);
+            newNode.getState().setPlayerNo(node.getState().getOpponent());
+            node.getChildArray().add(newNode);
+        });
+    }
+
+    private void backPropogation(Node nodeToExplore, int playerNo) {
+        Node tempNode = nodeToExplore;
+        while (tempNode != null) {
+            tempNode.getState().incrementVisit();
+            if (tempNode.getState().getPlayerNo() == playerNo)
+                tempNode.getState().addScore(WIN_SCORE);
+            tempNode = tempNode.getParent();
+        }
+    }
+
+    private int simulateRandomPlayout(Node node) {
+        Node tempNode = new Node(node);
+        State tempState = tempNode.getState();
+        int boardStatus = tempState.getBoard().checkStatus();
+
+        if (boardStatus == opponent) {
+            tempNode.getParent().getState().setWinScore(Integer.MIN_VALUE);
+            return boardStatus;
+        }
+        while (boardStatus == Board.IN_PROGRESS) {
+            tempState.togglePlayer();
+            tempState.randomPlay();
+            boardStatus = tempState.getBoard().checkStatus();
+        }
+
+        return boardStatus;
+    }
+
+}
--- a/algorithms-searching/src/main/java/com/baeldung/algorithms/mcts/montecarlo/State.java
+++ b/algorithms-searching/src/main/java/com/baeldung/algorithms/mcts/montecarlo/State.java
@@ -0,0 +1,97 @@
+package com.baeldung.algorithms.mcts.montecarlo;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.baeldung.algorithms.mcts.tictactoe.Board;
+import com.baeldung.algorithms.mcts.tictactoe.Position;
+
+public class State {
+    private Board board;
+    private int playerNo;
+    private int visitCount;
+    private double winScore;
+
+    public State() {
+        board = new Board();
+    }
+
+    public State(State state) {
+        this.board = new Board(state.getBoard());
+        this.playerNo = state.getPlayerNo();
+        this.visitCount = state.getVisitCount();
+        this.winScore = state.getWinScore();
+    }
+
+    public State(Board board) {
+        this.board = new Board(board);
+    }
+
+    Board getBoard() {
+        return board;
+    }
+
+    void setBoard(Board board) {
+        this.board = board;
+    }
+
+    int getPlayerNo() {
+        return playerNo;
+    }
+
+    void setPlayerNo(int playerNo) {
+        this.playerNo = playerNo;
+    }
+
+    int getOpponent() {
+        return 3 - playerNo;
+    }
+
+    public int getVisitCount() {
+        return visitCount;
+    }
+
+    public void setVisitCount(int visitCount) {
+        this.visitCount = visitCount;
+    }
+
+    double getWinScore() {
+        return winScore;
+    }
+
+    void setWinScore(double winScore) {
+        this.winScore = winScore;
+    }
+
+    public List<State> getAllPossibleStates() {
+        List<State> possibleStates = new ArrayList<>();
+        List<Position> availablePositions = this.board.getEmptyPositions();
+        availablePositions.forEach(p -> {
+            State newState = new State(this.board);
+            newState.setPlayerNo(3 - this.playerNo);
+            newState.getBoard().performMove(newState.getPlayerNo(), p);
+            possibleStates.add(newState);
+        });
+        return possibleStates;
+    }
+
+    void incrementVisit() {
+        this.visitCount++;
+    }
+
+    void addScore(double score) {
+        if (this.winScore != Integer.MIN_VALUE)
+            this.winScore += score;
+    }
+
+    void randomPlay() {
+        List<Position> availablePositions = this.board.getEmptyPositions();
+        int totalPossibilities = availablePositions.size();
+        int selectRandom = (int) (Math.random() * totalPossibilities);
+        this.board.performMove(this.playerNo, availablePositions.get(selectRandom));
+    }
+
+    void togglePlayer() {
+        this.playerNo = 3 - this.playerNo;
+    }
+}
--- a/algorithms-searching/src/main/java/com/baeldung/algorithms/mcts/montecarlo/UCT.java
+++ b/algorithms-searching/src/main/java/com/baeldung/algorithms/mcts/montecarlo/UCT.java
@@ -0,0 +1,24 @@
+package com.baeldung.algorithms.mcts.montecarlo;
+
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+import com.baeldung.algorithms.mcts.tree.Node;
+
+public class UCT {
+
+    public static double uctValue(int totalVisit, double nodeWinScore, int nodeVisit) {
+        if (nodeVisit == 0) {
+            return Integer.MAX_VALUE;
+        }
+        return (nodeWinScore / (double) nodeVisit) + 1.41 * Math.sqrt(Math.log(totalVisit) / (double) nodeVisit);
+    }
+
+    static Node findBestNodeWithUCT(Node node) {
+        int parentVisit = node.getState().getVisitCount();
+        return Collections.max(
+          node.getChildArray(),
+          Comparator.comparing(c -> uctValue(parentVisit, c.getState().getWinScore(), c.getState().getVisitCount())));
+    }
+}
--- a/algorithms-searching/src/main/java/com/baeldung/algorithms/mcts/tictactoe/Board.java
+++ b/algorithms-searching/src/main/java/com/baeldung/algorithms/mcts/tictactoe/Board.java
@@ -0,0 +1,155 @@
+package com.baeldung.algorithms.mcts.tictactoe;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class Board {
+    int[][] boardValues;
+    int totalMoves;
+
+    public static final int DEFAULT_BOARD_SIZE = 3;
+
+    public static final int IN_PROGRESS = -1;
+    public static final int DRAW = 0;
+    public static final int P1 = 1;
+    public static final int P2 = 2;
+
+    public Board() {
+        boardValues = new int[DEFAULT_BOARD_SIZE][DEFAULT_BOARD_SIZE];
+    }
+
+    public Board(int boardSize) {
+        boardValues = new int[boardSize][boardSize];
+    }
+
+    public Board(int[][] boardValues) {
+        this.boardValues = boardValues;
+    }
+
+    public Board(int[][] boardValues, int totalMoves) {
+        this.boardValues = boardValues;
+        this.totalMoves = totalMoves;
+    }
+
+    public Board(Board board) {
+        int boardLength = board.getBoardValues().length;
+        this.boardValues = new int[boardLength][boardLength];
+        int[][] boardValues = board.getBoardValues();
+        int n = boardValues.length;
+        for (int i = 0; i < n; i++) {
+            int m = boardValues[i].length;
+            for (int j = 0; j < m; j++) {
+                this.boardValues[i][j] = boardValues[i][j];
+            }
+        }
+    }
+
+    public void performMove(int player, Position p) {
+        this.totalMoves++;
+        boardValues[p.getX()][p.getY()] = player;
+    }
+
+    public int[][] getBoardValues() {
+        return boardValues;
+    }
+
+    public void setBoardValues(int[][] boardValues) {
+        this.boardValues = boardValues;
+    }
+
+    public int checkStatus() {
+        int boardSize = boardValues.length;
+        int maxIndex = boardSize - 1;
+        int[] diag1 = new int[boardSize];
+        int[] diag2 = new int[boardSize];
+        
+        for (int i = 0; i < boardSize; i++) {
+            int[] row = boardValues[i];
+            int[] col = new int[boardSize];
+            for (int j = 0; j < boardSize; j++) {
+                col[j] = boardValues[j][i];
+            }
+            
+            int checkRowForWin = checkForWin(row);
+            if(checkRowForWin!=0)
+                return checkRowForWin;
+            
+            int checkColForWin = checkForWin(col);
+            if(checkColForWin!=0)
+                return checkColForWin;
+            
+            diag1[i] = boardValues[i][i];
+            diag2[i] = boardValues[maxIndex - i][i];
+        }
+
+        int checkDia1gForWin = checkForWin(diag1);
+        if(checkDia1gForWin!=0)
+            return checkDia1gForWin;
+        
+        int checkDiag2ForWin = checkForWin(diag2);
+        if(checkDiag2ForWin!=0)
+            return checkDiag2ForWin;
+        
+        if (getEmptyPositions().size() > 0)
+            return IN_PROGRESS;
+        else
+            return DRAW;
+    }
+
+    private int checkForWin(int[] row) {
+        boolean isEqual = true;
+        int size = row.length;
+        int previous = row[0];
+        for (int i = 0; i < size; i++) {
+            if (previous != row[i]) {
+                isEqual = false;
+                break;
+            }
+            previous = row[i];
+        }
+        if(isEqual)
+            return previous;
+        else
+            return 0;
+    }
+
+    public void printBoard() {
+        int size = this.boardValues.length;
+        for (int i = 0; i < size; i++) {
+            for (int j = 0; j < size; j++) {
+                System.out.print(boardValues[i][j] + " ");
+            }
+            System.out.println();
+        }
+    }
+
+    public List<Position> getEmptyPositions() {
+        int size = this.boardValues.length;
+        List<Position> emptyPositions = new ArrayList<>();
+        for (int i = 0; i < size; i++) {
+            for (int j = 0; j < size; j++) {
+                if (boardValues[i][j] == 0)
+                    emptyPositions.add(new Position(i, j));
+            }
+        }
+        return emptyPositions;
+    }
+
+    public void printStatus() {
+        switch (this.checkStatus()) {
+        case P1:
+            System.out.println("Player 1 wins");
+            break;
+        case P2:
+            System.out.println("Player 2 wins");
+            break;
+        case DRAW:
+            System.out.println("Game Draw");
+            break;
+        case IN_PROGRESS:
+            System.out.println("Game In Progress");
+            break;
+        }
+    }
+}
--- a/algorithms-searching/src/main/java/com/baeldung/algorithms/mcts/tictactoe/Position.java
+++ b/algorithms-searching/src/main/java/com/baeldung/algorithms/mcts/tictactoe/Position.java
@@ -0,0 +1,31 @@
+package com.baeldung.algorithms.mcts.tictactoe;
+
+public class Position {
+    int x;
+    int y;
+
+    public Position() {
+    }
+
+    public Position(int x, int y) {
+        this.x = x;
+        this.y = y;
+    }
+
+    public int getX() {
+        return x;
+    }
+
+    public void setX(int x) {
+        this.x = x;
+    }
+
+    public int getY() {
+        return y;
+    }
+
+    public void setY(int y) {
+        this.y = y;
+    }
+
+}
--- a/algorithms-searching/src/main/java/com/baeldung/algorithms/mcts/tree/Node.java
+++ b/algorithms-searching/src/main/java/com/baeldung/algorithms/mcts/tree/Node.java
@@ -0,0 +1,78 @@
+package com.baeldung.algorithms.mcts.tree;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+import com.baeldung.algorithms.mcts.montecarlo.State;
+
+public class Node {
+    State state;
+    Node parent;
+    List<Node> childArray;
+
+    public Node() {
+        this.state = new State();
+        childArray = new ArrayList<>();
+    }
+
+    public Node(State state) {
+        this.state = state;
+        childArray = new ArrayList<>();
+    }
+
+    public Node(State state, Node parent, List<Node> childArray) {
+        this.state = state;
+        this.parent = parent;
+        this.childArray = childArray;
+    }
+
+    public Node(Node node) {
+        this.childArray = new ArrayList<>();
+        this.state = new State(node.getState());
+        if (node.getParent() != null)
+            this.parent = node.getParent();
+        List<Node> childArray = node.getChildArray();
+        for (Node child : childArray) {
+            this.childArray.add(new Node(child));
+        }
+    }
+
+    public State getState() {
+        return state;
+    }
+
+    public void setState(State state) {
+        this.state = state;
+    }
+
+    public Node getParent() {
+        return parent;
+    }
+
+    public void setParent(Node parent) {
+        this.parent = parent;
+    }
+
+    public List<Node> getChildArray() {
+        return childArray;
+    }
+
+    public void setChildArray(List<Node> childArray) {
+        this.childArray = childArray;
+    }
+
+    public Node getRandomChildNode() {
+        int noOfPossibleMoves = this.childArray.size();
+        int selectRandom = (int) (Math.random() * noOfPossibleMoves);
+        return this.childArray.get(selectRandom);
+    }
+
+    public Node getChildWithMaxScore() {
+        return Collections.max(this.childArray, Comparator.comparing(c -> {
+            return c.getState().getVisitCount();
+        }));
+    }
+
+}
--- a/algorithms-searching/src/main/java/com/baeldung/algorithms/mcts/tree/Tree.java
+++ b/algorithms-searching/src/main/java/com/baeldung/algorithms/mcts/tree/Tree.java
@@ -0,0 +1,26 @@
+package com.baeldung.algorithms.mcts.tree;
+
+public class Tree {
+    Node root;
+
+    public Tree() {
+        root = new Node();
+    }
+
+    public Tree(Node root) {
+        this.root = root;
+    }
+
+    public Node getRoot() {
+        return root;
+    }
+
+    public void setRoot(Node root) {
+        this.root = root;
+    }
+
+    public void addChild(Node parent, Node child) {
+        parent.getChildArray().add(child);
+    }
+
+}
--- a/algorithms-searching/src/main/java/com/baeldung/algorithms/textsearch/TextSearchAlgorithms.java
+++ b/algorithms-searching/src/main/java/com/baeldung/algorithms/textsearch/TextSearchAlgorithms.java
@@ -0,0 +1,194 @@
+package com.baeldung.algorithms.textsearch;
+
+import java.math.BigInteger;
+import java.util.Random;
+
+public class TextSearchAlgorithms {
+    public static long getBiggerPrime(int m) {
+        BigInteger prime = BigInteger.probablePrime(getNumberOfBits(m) + 1, new Random());
+        return prime.longValue();
+    }
+
+    public static long getLowerPrime(long number) {
+        BigInteger prime = BigInteger.probablePrime(getNumberOfBits(number) - 1, new Random());
+        return prime.longValue();
+    }
+
+    private static int getNumberOfBits(final int number) {
+        return Integer.SIZE - Integer.numberOfLeadingZeros(number);
+    }
+
+    private static int getNumberOfBits(final long number) {
+        return Long.SIZE - Long.numberOfLeadingZeros(number);
+    }
+
+    public static int simpleTextSearch(char[] pattern, char[] text) {
+        int patternSize = pattern.length;
+        int textSize = text.length;
+
+        int i = 0;
+
+        while ((i + patternSize) <= textSize) {
+            int j = 0;
+            while (text[i + j] == pattern[j]) {
+                j += 1;
+                if (j >= patternSize)
+                    return i;
+            }
+            i += 1;
+        }
+
+        return -1;
+    }
+
+    public static int RabinKarpMethod(char[] pattern, char[] text) {
+        int patternSize = pattern.length; // m
+        int textSize = text.length; // n
+
+        long prime = getBiggerPrime(patternSize);
+
+        long r = 1;
+        for (int i = 0; i < patternSize - 1; i++) {
+            r *= 2;
+            r = r % prime;
+        }
+
+        long[] t = new long[textSize];
+        t[0] = 0;
+
+        long pfinger = 0;
+
+        for (int j = 0; j < patternSize; j++) {
+            t[0] = (2 * t[0] + text[j]) % prime;
+            pfinger = (2 * pfinger + pattern[j]) % prime;
+        }
+
+        int i = 0;
+        boolean passed = false;
+
+        int diff = textSize - patternSize;
+        for (i = 0; i <= diff; i++) {
+            if (t[i] == pfinger) {
+                passed = true;
+                for (int k = 0; k < patternSize; k++) {
+                    if (text[i + k] != pattern[k]) {
+                        passed = false;
+                        break;
+                    }
+                }
+
+                if (passed) {
+                    return i;
+                }
+            }
+
+            if (i < diff) {
+                long value = 2 * (t[i] - r * text[i]) + text[i + patternSize];
+                t[i + 1] = ((value % prime) + prime) % prime;
+            }
+        }
+        return -1;
+
+    }
+
+    public static int KnuthMorrisPrattSearch(char[] pattern, char[] text) {
+        int patternSize = pattern.length; // m
+        int textSize = text.length; // n
+
+        int i = 0, j = 0;
+
+        int[] shift = KnuthMorrisPrattShift(pattern);
+
+        while ((i + patternSize) <= textSize) {
+            while (text[i + j] == pattern[j]) {
+                j += 1;
+                if (j >= patternSize)
+                    return i;
+            }
+
+            if (j > 0) {
+                i += shift[j - 1];
+                j = Math.max(j - shift[j - 1], 0);
+            } else {
+                i++;
+                j = 0;
+            }
+        }
+        return -1;
+    }
+
+    public static int[] KnuthMorrisPrattShift(char[] pattern) {
+        int patternSize = pattern.length;
+
+        int[] shift = new int[patternSize];
+        shift[0] = 1;
+
+        int i = 1, j = 0;
+
+        while ((i + j) < patternSize) {
+            if (pattern[i + j] == pattern[j]) {
+                shift[i + j] = i;
+                j++;
+            } else {
+                if (j == 0)
+                    shift[i] = i + 1;
+
+                if (j > 0) {
+                    i = i + shift[j - 1];
+                    j = Math.max(j - shift[j - 1], 0);
+                } else {
+                    i = i + 1;
+                    j = 0;
+                }
+            }
+        }
+        return shift;
+    }
+
+    public static int BoyerMooreHorspoolSimpleSearch(char[] pattern, char[] text) {
+        int patternSize = pattern.length;
+        int textSize = text.length;
+
+        int i = 0, j = 0;
+
+        while ((i + patternSize) <= textSize) {
+            j = patternSize - 1;
+            while (text[i + j] == pattern[j]) {
+                j--;
+                if (j < 0)
+                    return i;
+            }
+            i++;
+        }
+        return -1;
+    }
+
+    public static int BoyerMooreHorspoolSearch(char[] pattern, char[] text) {
+
+        int shift[] = new int[256];
+
+        for (int k = 0; k < 256; k++) {
+            shift[k] = pattern.length;
+        }
+
+        for (int k = 0; k < pattern.length - 1; k++) {
+            shift[pattern[k]] = pattern.length - 1 - k;
+        }
+
+        int i = 0, j = 0;
+
+        while ((i + pattern.length) <= text.length) {
+            j = pattern.length - 1;
+
+            while (text[i + j] == pattern[j]) {
+                j -= 1;
+                if (j < 0)
+                    return i;
+            }
+
+            i = i + shift[text[i + pattern.length - 1]];
+
+        }
+        return -1;
+    }
+}
--- a/algorithms-searching/src/main/resources/logback.xml
+++ b/algorithms-searching/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>
--- a/algorithms-searching/src/test/java/com/baeldung/algorithms/binarysearch/BinarySearchUnitTest.java
+++ b/algorithms-searching/src/test/java/com/baeldung/algorithms/binarysearch/BinarySearchUnitTest.java
@@ -0,0 +1,41 @@
+package com.baeldung.algorithms.binarysearch;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class BinarySearchUnitTest {
+
+    int[] sortedArray = { 0, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 9 };
+    int key = 6;
+    int expectedIndexForSearchKey = 7;
+    int low = 0;
+    int high = sortedArray.length - 1;
+    List<Integer> sortedList = Arrays.asList(0, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 9);
+    
+    @Test
+    public void givenASortedArrayOfIntegers_whenBinarySearchRunIterativelyForANumber_thenGetIndexOfTheNumber() {
+        BinarySearch binSearch = new BinarySearch();
+        Assert.assertEquals(expectedIndexForSearchKey, binSearch.runBinarySearchIteratively(sortedArray, key, low, high));
+    }
+
+    @Test
+    public void givenASortedArrayOfIntegers_whenBinarySearchRunRecursivelyForANumber_thenGetIndexOfTheNumber() {
+        BinarySearch binSearch = new BinarySearch();
+        Assert.assertEquals(expectedIndexForSearchKey, binSearch.runBinarySearchRecursively(sortedArray, key, low, high));
+    }
+    
+    @Test
+    public void givenASortedArrayOfIntegers_whenBinarySearchRunUsingArraysClassStaticMethodForANumber_thenGetIndexOfTheNumber() {
+        BinarySearch binSearch = new BinarySearch();
+        Assert.assertEquals(expectedIndexForSearchKey, binSearch.runBinarySearchUsingJavaArrays(sortedArray, key));
+    }
+    
+    @Test
+    public void givenASortedListOfIntegers_whenBinarySearchRunUsingCollectionsClassStaticMethodForANumber_thenGetIndexOfTheNumber() {
+        BinarySearch binSearch = new BinarySearch();
+        Assert.assertEquals(expectedIndexForSearchKey, binSearch.runBinarySearchUsingJavaCollections(sortedList, key));
+    }
+    
+}
--- a/algorithms-searching/src/test/java/com/baeldung/algorithms/breadthfirstsearch/BreadthFirstSearchAlgorithmUnitTest.java
+++ b/algorithms-searching/src/test/java/com/baeldung/algorithms/breadthfirstsearch/BreadthFirstSearchAlgorithmUnitTest.java
@@ -0,0 +1,86 @@
+package com.baeldung.algorithms.breadthfirstsearch;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class BreadthFirstSearchAlgorithmUnitTest {
+
+    private Tree<Integer> root;
+    private Tree<Integer> rootFirstChild;
+    private Tree<Integer> depthMostChild;
+    private Tree<Integer> rootSecondChild;
+
+    private Node<Integer> start;
+    private Node<Integer> firstNeighbor;
+    private Node<Integer> firstNeighborNeighbor;
+    private Node<Integer> secondNeighbor;
+
+    @Test
+    void givenTree_whenSearchTen_thenRoot() {
+        initTree();
+        assertThat(BreadthFirstSearchAlgorithm.search(10, root)).isPresent().contains(root);
+    }
+
+    @Test
+    void givenTree_whenSearchThree_thenDepthMostValue() {
+        initTree();
+        assertThat(BreadthFirstSearchAlgorithm.search(3, root)).isPresent().contains(depthMostChild);
+    }
+
+    @Test
+    void givenTree_whenSearchFour_thenRootSecondChild() {
+        initTree();
+        assertThat(BreadthFirstSearchAlgorithm.search(4, root)).isPresent().contains(rootSecondChild);
+    }
+
+    @Test
+    void givenTree_whenSearchFive_thenNotFound() {
+        initTree();
+        assertThat(BreadthFirstSearchAlgorithm.search(5, root)).isEmpty();
+    }
+
+    private void initTree() {
+        root = Tree.of(10);
+        rootFirstChild = root.addChild(2);
+        depthMostChild = rootFirstChild.addChild(3);
+        rootSecondChild = root.addChild(4);
+    }
+
+    @Test
+    void givenNode_whenSearchTen_thenStart() {
+        initNode();
+        assertThat(BreadthFirstSearchAlgorithm.search(10, firstNeighborNeighbor)).isPresent().contains(start);
+    }
+
+    @Test
+    void givenNode_whenSearchThree_thenNeighborNeighbor() {
+        initNode();
+        assertThat(BreadthFirstSearchAlgorithm.search(3, firstNeighborNeighbor)).isPresent().contains(firstNeighborNeighbor);
+    }
+
+    @Test
+    void givenNode_whenSearchFour_thenSecondNeighbor() {
+        initNode();
+        assertThat(BreadthFirstSearchAlgorithm.search(4, firstNeighborNeighbor)).isPresent().contains(secondNeighbor);
+    }
+
+    @Test
+    void givenNode_whenSearchFive_thenNotFound() {
+        initNode();
+        assertThat(BreadthFirstSearchAlgorithm.search(5, firstNeighborNeighbor)).isEmpty();
+    }
+
+    private void initNode() {
+        start = new Node<>(10);
+        firstNeighbor = new Node<>(2);
+        start.connect(firstNeighbor);
+
+        firstNeighborNeighbor = new Node<>(3);
+        firstNeighbor.connect(firstNeighborNeighbor);
+        firstNeighborNeighbor.connect(start);
+
+        secondNeighbor = new Node<>(4);
+        start.connect(secondNeighbor);
+    }
+}
--- a/algorithms-searching/src/test/java/com/baeldung/algorithms/dfs/BinaryTreeUnitTest.java
+++ b/algorithms-searching/src/test/java/com/baeldung/algorithms/dfs/BinaryTreeUnitTest.java
@@ -0,0 +1,136 @@
+package com.baeldung.algorithms.dfs;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+public class BinaryTreeUnitTest {
+
+    @Test
+    public void givenABinaryTree_WhenAddingElements_ThenTreeNotEmpty() {
+
+        BinaryTree bt = createBinaryTree();
+
+        assertTrue(!bt.isEmpty());
+    }
+
+    @Test
+    public void givenABinaryTree_WhenAddingElements_ThenTreeContainsThoseElements() {
+
+        BinaryTree bt = createBinaryTree();
+
+        assertTrue(bt.containsNode(6));
+        assertTrue(bt.containsNode(4));
+
+        assertFalse(bt.containsNode(1));
+    }
+
+    @Test
+    public void givenABinaryTree_WhenAddingExistingElement_ThenElementIsNotAdded() {
+
+        BinaryTree bt = createBinaryTree();
+
+        int initialSize = bt.getSize();
+
+        assertTrue(bt.containsNode(3));
+        bt.add(3);
+        assertEquals(initialSize, bt.getSize());
+    }
+
+    @Test
+    public void givenABinaryTree_WhenLookingForNonExistingElement_ThenReturnsFalse() {
+
+        BinaryTree bt = createBinaryTree();
+
+        assertFalse(bt.containsNode(99));
+    }
+
+    @Test
+    public void givenABinaryTree_WhenDeletingElements_ThenTreeDoesNotContainThoseElements() {
+
+        BinaryTree bt = createBinaryTree();
+
+        assertTrue(bt.containsNode(9));
+        bt.delete(9);
+        assertFalse(bt.containsNode(9));
+    }
+
+    @Test
+    public void givenABinaryTree_WhenDeletingNonExistingElement_ThenTreeDoesNotDelete() {
+
+        BinaryTree bt = createBinaryTree();
+
+        int initialSize = bt.getSize();
+
+        assertFalse(bt.containsNode(99));
+        bt.delete(99);
+        assertFalse(bt.containsNode(99));
+        assertEquals(initialSize, bt.getSize());
+    }
+
+    @Test
+    public void it_deletes_the_root() {
+        int value = 12;
+        BinaryTree bt = new BinaryTree();
+        bt.add(value);
+
+        assertTrue(bt.containsNode(value));
+        bt.delete(value);
+        assertFalse(bt.containsNode(value));
+    }
+
+    @Test
+    public void givenABinaryTree_WhenTraversingInOrder_ThenPrintValues() {
+
+        BinaryTree bt = createBinaryTree();
+
+        bt.traverseInOrder(bt.root);
+        System.out.println();
+        bt.traverseInOrderWithoutRecursion();
+    }
+
+    @Test
+    public void givenABinaryTree_WhenTraversingPreOrder_ThenPrintValues() {
+
+        BinaryTree bt = createBinaryTree();
+
+        bt.traversePreOrder(bt.root);
+        System.out.println();
+        bt.traversePreOrderWithoutRecursion();
+    }
+
+    @Test
+    public void givenABinaryTree_WhenTraversingPostOrder_ThenPrintValues() {
+
+        BinaryTree bt = createBinaryTree();
+
+        bt.traversePostOrder(bt.root);
+        System.out.println();
+        bt.traversePostOrderWithoutRecursion();
+    }
+
+    @Test
+    public void givenABinaryTree_WhenTraversingLevelOrder_ThenPrintValues() {
+
+        BinaryTree bt = createBinaryTree();
+
+        bt.traverseLevelOrder();
+    }
+
+    private BinaryTree createBinaryTree() {
+        BinaryTree bt = new BinaryTree();
+
+        bt.add(6);
+        bt.add(4);
+        bt.add(8);
+        bt.add(3);
+        bt.add(5);
+        bt.add(7);
+        bt.add(9);
+
+        return bt;
+    }
+
+}
--- a/algorithms-searching/src/test/java/com/baeldung/algorithms/dfs/GraphUnitTest.java
+++ b/algorithms-searching/src/test/java/com/baeldung/algorithms/dfs/GraphUnitTest.java
@@ -0,0 +1,41 @@
+package com.baeldung.algorithms.dfs;
+
+import java.util.List;
+
+import com.baeldung.algorithms.dfs.Graph;
+import org.junit.Test;
+
+public class GraphUnitTest {
+
+    @Test
+    public void givenDirectedGraph_whenDFS_thenPrintAllValues() {
+        Graph graph = createDirectedGraph();
+        graph.dfs(0);
+        System.out.println();
+        graph.dfsWithoutRecursion(0);
+    }
+
+    @Test
+    public void givenDirectedGraph_whenGetTopologicalSort_thenPrintValuesSorted() {
+        Graph graph = createDirectedGraph();
+        List<Integer> list = graph.topologicalSort(0);
+        System.out.println(list);
+    }
+
+    private Graph createDirectedGraph() {
+        Graph graph = new Graph();
+        graph.addVertex(0);
+        graph.addVertex(1);
+        graph.addVertex(2);
+        graph.addVertex(3);
+        graph.addVertex(4);
+        graph.addVertex(5);
+        graph.addEdge(0, 1);
+        graph.addEdge(0, 2);
+        graph.addEdge(1, 3);
+        graph.addEdge(2, 3);
+        graph.addEdge(3, 4);
+        graph.addEdge(4, 5);
+        return graph;
+    }
+}
--- a/algorithms-searching/src/test/java/com/baeldung/algorithms/interpolationsearch/InterpolationSearchUnitTest.java
+++ b/algorithms-searching/src/test/java/com/baeldung/algorithms/interpolationsearch/InterpolationSearchUnitTest.java
@@ -0,0 +1,29 @@
+package com.baeldung.algorithms.interpolationsearch;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class InterpolationSearchUnitTest {
+    
+    private int[] myData;
+
+    @Before
+    public void setUp() {
+        myData = new int[]{13,21,34,55,69,73,84,101};
+    }
+    
+    @Test
+    public void givenSortedArray_whenLookingFor84_thenReturn6() {
+        int pos = InterpolationSearch.interpolationSearch(myData, 84);
+        assertEquals(6, pos);
+    }
+    
+    @Test
+    public void givenSortedArray_whenLookingFor19_thenReturnMinusOne() {
+        int pos = InterpolationSearch.interpolationSearch(myData, 19);
+        assertEquals(-1, pos);
+    }
+
+}
--- a/algorithms-searching/src/test/java/com/baeldung/algorithms/mcts/MCTSUnitTest.java
+++ b/algorithms-searching/src/test/java/com/baeldung/algorithms/mcts/MCTSUnitTest.java
@@ -0,0 +1,92 @@
+package com.baeldung.algorithms.mcts;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import com.baeldung.algorithms.mcts.montecarlo.MonteCarloTreeSearch;
+import com.baeldung.algorithms.mcts.montecarlo.State;
+import com.baeldung.algorithms.mcts.montecarlo.UCT;
+import com.baeldung.algorithms.mcts.tictactoe.Board;
+import com.baeldung.algorithms.mcts.tictactoe.Position;
+import com.baeldung.algorithms.mcts.tree.Tree;
+
+public class MCTSUnitTest {
+    private Tree gameTree;
+    private MonteCarloTreeSearch mcts;
+
+    @Before
+    public void initGameTree() {
+        gameTree = new Tree();
+        mcts = new MonteCarloTreeSearch();
+    }
+
+    @Test
+    public void givenStats_whenGetUCTForNode_thenUCTMatchesWithManualData() {
+        double uctValue = 15.79;
+        assertEquals(UCT.uctValue(600, 300, 20), uctValue, 0.01);
+    }
+
+    @Test
+    public void giveninitBoardState_whenGetAllPossibleStates_thenNonEmptyList() {
+        State initState = gameTree.getRoot().getState();
+        List<State> possibleStates = initState.getAllPossibleStates();
+        assertTrue(possibleStates.size() > 0);
+    }
+
+    @Test
+    public void givenEmptyBoard_whenPerformMove_thenLessAvailablePossitions() {
+        Board board = new Board();
+        int initAvailablePositions = board.getEmptyPositions().size();
+        board.performMove(Board.P1, new Position(1, 1));
+        int availablePositions = board.getEmptyPositions().size();
+        assertTrue(initAvailablePositions > availablePositions);
+    }
+
+    @Test
+    public void givenEmptyBoard_whenSimulateInterAIPlay_thenGameDraw() {
+        Board board = new Board();
+
+        int player = Board.P1;
+        int totalMoves = Board.DEFAULT_BOARD_SIZE * Board.DEFAULT_BOARD_SIZE;
+        for (int i = 0; i < totalMoves; i++) {
+            board = mcts.findNextMove(board, player);
+            if (board.checkStatus() != -1) {
+                break;
+            }
+            player = 3 - player;
+        }
+        int winStatus = board.checkStatus();
+        assertEquals(winStatus, Board.DRAW);
+    }
+
+    @Test
+    public void givenEmptyBoard_whenLevel1VsLevel3_thenLevel3WinsOrDraw() {
+        Board board = new Board();
+        MonteCarloTreeSearch mcts1 = new MonteCarloTreeSearch();
+        mcts1.setLevel(1);
+        MonteCarloTreeSearch mcts3 = new MonteCarloTreeSearch();
+        mcts3.setLevel(3);
+
+        int player = Board.P1;
+        int totalMoves = Board.DEFAULT_BOARD_SIZE * Board.DEFAULT_BOARD_SIZE;
+        for (int i = 0; i < totalMoves; i++) {
+            if (player == Board.P1)
+                board = mcts3.findNextMove(board, player);
+            else
+                board = mcts1.findNextMove(board, player);
+
+            if (board.checkStatus() != -1) {
+                break;
+            }
+            player = 3 - player;
+        }
+        int winStatus = board.checkStatus();
+        assertTrue(winStatus == Board.DRAW || winStatus == Board.P1);
+    }
+
+}
--- a/algorithms-searching/src/test/java/com/baeldung/algorithms/textsearch/TextSearchAlgorithmsUnitTest.java
+++ b/algorithms-searching/src/test/java/com/baeldung/algorithms/textsearch/TextSearchAlgorithmsUnitTest.java
@@ -0,0 +1,23 @@
+package com.baeldung.algorithms.textsearch;
+
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class TextSearchAlgorithmsUnitTest {
+
+
+    @Test
+    public void testStringSearchAlgorithms() {
+        String text = "This is some nice text.";
+        String pattern = "some";
+
+        int realPosition = text.indexOf(pattern);
+        Assert.assertTrue(realPosition == TextSearchAlgorithms.simpleTextSearch(pattern.toCharArray(), text.toCharArray()));
+        Assert.assertTrue(realPosition == TextSearchAlgorithms.RabinKarpMethod(pattern.toCharArray(), text.toCharArray()));
+        Assert.assertTrue(realPosition == TextSearchAlgorithms.KnuthMorrisPrattSearch(pattern.toCharArray(), text.toCharArray()));
+        Assert.assertTrue(realPosition == TextSearchAlgorithms.BoyerMooreHorspoolSimpleSearch(pattern.toCharArray(), text.toCharArray()));
+        Assert.assertTrue(realPosition == TextSearchAlgorithms.BoyerMooreHorspoolSearch(pattern.toCharArray(), text.toCharArray()));
+    }
+
+}