[BAEL-9551] - Splitted algorithms into 4 modules

This commit is contained in:
amit2103
2018-10-28 23:29:09 +05:30
parent c10101a9ac
commit 539ce3e787
164 changed files with 1735 additions and 1241 deletions

4
algorithms-miscellaneous-2/.gitignore vendored Normal file
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/target/
.settings/
.classpath
.project

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## Relevant articles:
- [Dijkstra Algorithm in Java](http://www.baeldung.com/java-dijkstra)
- [Introduction to Cobertura](http://www.baeldung.com/cobertura)
- [Test a Linked List for Cyclicity](http://www.baeldung.com/java-linked-list-cyclicity)
- [Introduction to JGraphT](http://www.baeldung.com/jgrapht)
- [A Maze Solver in Java](http://www.baeldung.com/java-solve-maze)
- [Create a Sudoku Solver in Java](http://www.baeldung.com/java-sudoku)
- [Displaying Money Amounts in Words](http://www.baeldung.com/java-money-into-words)
- [A Collaborative Filtering Recommendation System in Java](http://www.baeldung.com/java-collaborative-filtering-recommendations)
- [Converting Between Roman and Arabic Numerals in Java](http://www.baeldung.com/java-convert-roman-arabic)
- [Practical Java Examples of the Big O Notation](http://www.baeldung.com/java-algorithm-complexity)
- [Find the Middle Element of a Linked List](http://www.baeldung.com/java-linked-list-middle-element)
- [An Introduction to the Theory of Big-O Notation](http://www.baeldung.com/big-o-notation)
- [Check If Two Rectangles Overlap In Java](https://www.baeldung.com/java-check-if-two-rectangles-overlap)
- [Calculate the Distance Between Two Points in Java](https://www.baeldung.com/java-distance-between-two-points)
- [Find the Intersection of Two Lines in Java](https://www.baeldung.com/java-intersection-of-two-lines)
- [Round Up to the Nearest Hundred](https://www.baeldung.com/java-round-up-nearest-hundred)
- [Calculate Percentage in Java](https://www.baeldung.com/java-calculate-percentage)
- [Converting Between Byte Arrays and Hexadecimal Strings in Java](https://www.baeldung.com/java-byte-arrays-hex-strings)

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<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>
<groupId>com.baeldung</groupId>
<artifactId>algorithms-miscellaneous-2</artifactId>
<version>0.0.1-SNAPSHOT</version>
<parent>
<groupId>com.baeldung</groupId>
<artifactId>parent-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>
<dependency>
<groupId>org.jgrapht</groupId>
<artifactId>jgrapht-core</artifactId>
<version>${org.jgrapht.core.version}</version>
</dependency>
<dependency>
<groupId>pl.allegro.finance</groupId>
<artifactId>tradukisto</artifactId>
<version>${tradukisto.version}</version>
</dependency>
<dependency>
<groupId>org.assertj</groupId>
<artifactId>assertj-core</artifactId>
<version>${org.assertj.core.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>${exec-maven-plugin.version}</version>
</plugin>
</plugins>
</pluginManagement>
</build>
<reporting>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>cobertura-maven-plugin</artifactId>
<version>2.7</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>
<lombok.version>1.16.12</lombok.version>
<commons-math3.version>3.6.1</commons-math3.version>
<tradukisto.version>1.0.1</tradukisto.version>
<io.jenetics.version>3.7.0</io.jenetics.version>
<org.jgrapht.core.version>1.0.1</org.jgrapht.core.version>
<org.assertj.core.version>3.9.0</org.assertj.core.version>
<commons-codec.version>1.11</commons-codec.version>
</properties>
</project>

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/bin/

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package com.java.src;
import java.util.Scanner;
public class RoundUpToHundred {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
double input = scanner.nextDouble();
scanner.close();
RoundUpToHundred.round(input);
}
static long round(double input) {
long i = (long) Math.ceil(input);
return ((i + 99) / 100) * 100;
};
}

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package com.java.src;
import static org.junit.Assert.assertEquals;
import org.junit.Test;
public class RoundUpToHundredTest {
@Test
public void givenInput_whenRound_thenRoundUpToTheNearestHundred() {
assertEquals("Rounded up to hundred", 100, RoundUpToHundred.round(99));
assertEquals("Rounded up to three hundred ", 300, RoundUpToHundred.round(200.2));
assertEquals("Returns same rounded value", 400, RoundUpToHundred.round(400));
}
}

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package com.baeldung.algorithms.conversion;
import java.math.BigInteger;
import javax.xml.bind.DatatypeConverter;
import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Hex;
import com.google.common.io.BaseEncoding;
public class HexStringConverter {
/**
* Create a byte Array from String of hexadecimal digits using Character conversion
* @param hexString - Hexadecimal digits as String
* @return Desired byte Array
*/
public byte[] decodeHexString(String hexString) {
if (hexString.length() % 2 == 1) {
throw new IllegalArgumentException("Invalid hexadecimal String supplied.");
}
byte[] bytes = new byte[hexString.length() / 2];
for (int i = 0; i < hexString.length(); i += 2) {
bytes[i / 2] = hexToByte(hexString.substring(i, i + 2));
}
return bytes;
}
/**
* Create a String of hexadecimal digits from a byte Array using Character conversion
* @param byteArray - The byte Array
* @return Desired String of hexadecimal digits in lower case
*/
public String encodeHexString(byte[] byteArray) {
StringBuffer hexStringBuffer = new StringBuffer();
for (int i = 0; i < byteArray.length; i++) {
hexStringBuffer.append(byteToHex(byteArray[i]));
}
return hexStringBuffer.toString();
}
public String byteToHex(byte num) {
char[] hexDigits = new char[2];
hexDigits[0] = Character.forDigit((num >> 4) & 0xF, 16);
hexDigits[1] = Character.forDigit((num & 0xF), 16);
return new String(hexDigits);
}
public byte hexToByte(String hexString) {
int firstDigit = toDigit(hexString.charAt(0));
int secondDigit = toDigit(hexString.charAt(1));
return (byte) ((firstDigit << 4) + secondDigit);
}
private int toDigit(char hexChar) {
int digit = Character.digit(hexChar, 16);
if(digit == -1) {
throw new IllegalArgumentException("Invalid Hexadecimal Character: "+ hexChar);
}
return digit;
}
public String encodeUsingBigIntegerToString(byte[] bytes) {
BigInteger bigInteger = new BigInteger(1, bytes);
return bigInteger.toString(16);
}
public String encodeUsingBigIntegerStringFormat(byte[] bytes) {
BigInteger bigInteger = new BigInteger(1, bytes);
return String.format("%0" + (bytes.length << 1) + "x", bigInteger);
}
public byte[] decodeUsingBigInteger(String hexString) {
byte[] byteArray = new BigInteger(hexString, 16).toByteArray();
if (byteArray[0] == 0) {
byte[] output = new byte[byteArray.length - 1];
System.arraycopy(byteArray, 1, output, 0, output.length);
return output;
}
return byteArray;
}
public String encodeUsingDataTypeConverter(byte[] bytes) {
return DatatypeConverter.printHexBinary(bytes);
}
public byte[] decodeUsingDataTypeConverter(String hexString) {
return DatatypeConverter.parseHexBinary(hexString);
}
public String encodeUsingApacheCommons(byte[] bytes) throws DecoderException {
return Hex.encodeHexString(bytes);
}
public byte[] decodeUsingApacheCommons(String hexString) throws DecoderException {
return Hex.decodeHex(hexString);
}
public String encodeUsingGuava(byte[] bytes) {
return BaseEncoding.base16()
.encode(bytes);
}
public byte[] decodeUsingGuava(String hexString) {
return BaseEncoding.base16()
.decode(hexString.toUpperCase());
}
}

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package com.baeldung.algorithms.distancebetweenpoints;
import java.awt.geom.Point2D;
public class DistanceBetweenPointsService {
public double calculateDistanceBetweenPoints(
double x1,
double y1,
double x2,
double y2) {
return Math.sqrt((y2 - y1) * (y2 - y1) + (x2 - x1) * (x2 - x1));
}
public double calculateDistanceBetweenPointsWithHypot(
double x1,
double y1,
double x2,
double y2) {
double ac = Math.abs(y2 - y1);
double cb = Math.abs(x2 - x1);
return Math.hypot(ac, cb);
}
public double calculateDistanceBetweenPointsWithPoint2D(
double x1,
double y1,
double x2,
double y2) {
return Point2D.distance(x1, y1, x2, y2);
}
}

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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);
}
}

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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()];
}
}

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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);
}
}

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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);
}
}

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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);
}
}

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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);
}
}

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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;
}
}

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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;
}
}

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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;
}
}

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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;
}
}

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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;
}
}

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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;
}
}

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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;
}
}

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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);
}
}

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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);
}
}

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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();
}
}

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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);
}
}

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package com.baeldung.algorithms.rectanglesoverlap;
public class Point {
private int x;
private int y;
public Point(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;
}
}

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package com.baeldung.algorithms.rectanglesoverlap;
public class Rectangle {
private Point bottomLeft;
private Point topRight;
public Rectangle(Point bottomLeft, Point topRight) {
this.bottomLeft = bottomLeft;
this.topRight = topRight;
}
public Point getBottomLeft() {
return bottomLeft;
}
public void setBottomLeft(Point bottomLeft) {
this.bottomLeft = bottomLeft;
}
public Point getTopRight() {
return topRight;
}
public void setTopRight(Point topRight) {
this.topRight = topRight;
}
public boolean isOverlapping(Rectangle other) {
// one rectangle is to the top of the other
if (this.topRight.getY() < other.bottomLeft.getY() || this.bottomLeft.getY() > other.topRight.getY()) {
return false;
}
// one rectangle is to the left of the other
if (this.topRight.getX() < other.bottomLeft.getX() || this.bottomLeft.getX() > other.topRight.getX()) {
return false;
}
return true;
}
}

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package com.baeldung.algorithms.romannumerals;
import java.util.List;
class RomanArabicConverter {
public static int romanToArabic(String input) {
String romanNumeral = input.toUpperCase();
int result = 0;
List<RomanNumeral> romanNumerals = RomanNumeral.getReverseSortedValues();
int i = 0;
while ((romanNumeral.length() > 0) && (i < romanNumerals.size())) {
RomanNumeral symbol = romanNumerals.get(i);
if (romanNumeral.startsWith(symbol.name())) {
result += symbol.getValue();
romanNumeral = romanNumeral.substring(symbol.name().length());
} else {
i++;
}
}
if (romanNumeral.length() > 0) {
throw new IllegalArgumentException(input + " cannot be converted to a Roman Numeral");
}
return result;
}
public static String arabicToRoman(int number) {
if ((number <= 0) || (number > 4000)) {
throw new IllegalArgumentException(number + " is not in range (0,4000]");
}
List<RomanNumeral> romanNumerals = RomanNumeral.getReverseSortedValues();
int i = 0;
StringBuilder sb = new StringBuilder();
while (number > 0 && i < romanNumerals.size()) {
RomanNumeral currentSymbol = romanNumerals.get(i);
if (currentSymbol.getValue() <= number) {
sb.append(currentSymbol.name());
number -= currentSymbol.getValue();
} else {
i++;
}
}
return sb.toString();
}
}

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package com.baeldung.algorithms.romannumerals;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;
enum RomanNumeral {
I(1), IV(4), V(5), IX(9), X(10), XL(40), L(50), XC(90), C(100), CD(400), D(500), CM(900), M(1000);
private int value;
RomanNumeral(int value) {
this.value = value;
}
public int getValue() {
return value;
}
public static List<RomanNumeral> getReverseSortedValues() {
return Arrays.stream(values())
.sorted(Comparator.comparing((RomanNumeral e) -> e.value).reversed())
.collect(Collectors.toList());
}
}

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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;
}
}

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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();
}
}

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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();
}
}

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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;
}
}

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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;
}
}

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<?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>

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

View File

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

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package com.baeldung.algorithms.analysis;
import org.junit.Test;
public class AnalysisRunnerLiveTest {
int n = 10;
int total = 0;
@Test
public void whenConstantComplexity_thenConstantRuntime() {
System.out.println("**** n = " + n + " ****");
System.out.println();
// Constant Time
System.out.println("**** Constant time ****");
System.out.println("Hey - your input is: " + n);
System.out.println("Running time not dependent on input size!");
System.out.println();
}
@Test
public void whenLogarithmicComplexity_thenLogarithmicRuntime() {
// Logarithmic Time
System.out.println("**** Logarithmic Time ****");
for (int i = 1; i < n; i = i * 2) {
// System.out.println("Hey - I'm busy looking at: " + i);
total++;
}
System.out.println("Total amount of times run: " + total);
System.out.println();
}
@Test
public void whenLinearComplexity_thenLinearRuntime() {
// Linear Time
System.out.println("**** Linear Time ****");
for (int i = 0; i < n; i++) {
// System.out.println("Hey - I'm busy looking at: " + i);
total++;
}
System.out.println("Total amount of times run: " + total);
System.out.println();
}
@Test
public void whenNLogNComplexity_thenNLogNRuntime() {
// N Log N Time
System.out.println("**** nlogn Time ****");
total = 0;
for (
int i = 1; i <= n; i++) {
for (int j = 1; j < n; j = j * 2) {
// System.out.println("Hey - I'm busy looking at: " + i + " and " + j);
total++;
}
}
System.out.println("Total amount of times run: " + total);
System.out.println();
}
@Test
public void whenQuadraticComplexity_thenQuadraticRuntime() {
// Quadratic Time
System.out.println("**** Quadratic Time ****");
total = 0;
for (
int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
// System.out.println("Hey - I'm busy looking at: " + i + " and " + j);
total++;
}
}
System.out.println("Total amount of times run: " + total);
System.out.println();
}
@Test
public void whenCubicComplexity_thenCubicRuntime() {
// Cubic Time
System.out.println("**** Cubic Time ****");
total = 0;
for (
int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
for (int k = 1; k <= n; k++) {
// System.out.println("Hey - I'm busy looking at: " + i + " and " + j + " and " + k);
total++;
}
}
}
System.out.println("Total amount of times run: " + total);
System.out.println();
}
@Test
public void whenExponentialComplexity_thenExponentialRuntime() {
// Exponential Time
System.out.println("**** Exponential Time ****");
total = 0;
for (
int i = 1; i <= Math.pow(2, n); i++) {
// System.out.println("Hey - I'm busy looking at: " + i);
total++;
}
System.out.println("Total amount of times run: " + total);
System.out.println();
}
@Test
public void whenFactorialComplexity_thenFactorialRuntime() {
// Factorial Time
System.out.println("**** Factorial Time ****");
total = 0;
for (
int i = 1; i <=
factorial(n); i++) {
// System.out.println("Hey - I'm busy looking at: " + i);
total++;
}
System.out.println("Total amount of times run: " + total);
}
static int factorial(int n) {
if (n == 0 || n == 1)
return 1;
else
return n * factorial(n - 1);
}
}

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package com.baeldung.algorithms.conversion;
import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertThat;
import org.apache.commons.codec.DecoderException;
import org.hamcrest.text.IsEqualIgnoringCase;
import org.junit.Before;
import org.junit.Test;
import com.baeldung.algorithms.conversion.HexStringConverter;
public class ByteArrayConverterUnitTest {
private HexStringConverter hexStringConverter;
@Before
public void setup() {
hexStringConverter = new HexStringConverter();
}
@Test
public void shouldEncodeByteArrayToHexStringUsingBigIntegerToString() {
byte[] bytes = getSampleBytes();
String hexString = getSampleHexString();
if(hexString.charAt(0) == '0') {
hexString = hexString.substring(1);
}
String output = hexStringConverter.encodeUsingBigIntegerToString(bytes);
assertThat(output, IsEqualIgnoringCase.equalToIgnoringCase(hexString));
}
@Test
public void shouldEncodeByteArrayToHexStringUsingBigIntegerStringFormat() {
byte[] bytes = getSampleBytes();
String hexString = getSampleHexString();
String output = hexStringConverter.encodeUsingBigIntegerStringFormat(bytes);
assertThat(output, IsEqualIgnoringCase.equalToIgnoringCase(hexString));
}
@Test
public void shouldDecodeHexStringToByteArrayUsingBigInteger() {
byte[] bytes = getSampleBytes();
String hexString = getSampleHexString();
byte[] output = hexStringConverter.decodeUsingBigInteger(hexString);
assertArrayEquals(bytes, output);
}
@Test
public void shouldEncodeByteArrayToHexStringUsingCharacterConversion() {
byte[] bytes = getSampleBytes();
String hexString = getSampleHexString();
String output = hexStringConverter.encodeHexString(bytes);
assertThat(output, IsEqualIgnoringCase.equalToIgnoringCase(hexString));
}
@Test
public void shouldDecodeHexStringToByteArrayUsingCharacterConversion() {
byte[] bytes = getSampleBytes();
String hexString = getSampleHexString();
byte[] output = hexStringConverter.decodeHexString(hexString);
assertArrayEquals(bytes, output);
}
@Test(expected=IllegalArgumentException.class)
public void shouldDecodeHexToByteWithInvalidHexCharacter() {
hexStringConverter.hexToByte("fg");
}
@Test
public void shouldEncodeByteArrayToHexStringDataTypeConverter() {
byte[] bytes = getSampleBytes();
String hexString = getSampleHexString();
String output = hexStringConverter.encodeUsingDataTypeConverter(bytes);
assertThat(output, IsEqualIgnoringCase.equalToIgnoringCase(hexString));
}
@Test
public void shouldDecodeHexStringToByteArrayUsingDataTypeConverter() {
byte[] bytes = getSampleBytes();
String hexString = getSampleHexString();
byte[] output = hexStringConverter.decodeUsingDataTypeConverter(hexString);
assertArrayEquals(bytes, output);
}
@Test
public void shouldEncodeByteArrayToHexStringUsingGuava() {
byte[] bytes = getSampleBytes();
String hexString = getSampleHexString();
String output = hexStringConverter.encodeUsingGuava(bytes);
assertThat(output, IsEqualIgnoringCase.equalToIgnoringCase(hexString));
}
@Test
public void shouldDecodeHexStringToByteArrayUsingGuava() {
byte[] bytes = getSampleBytes();
String hexString = getSampleHexString();
byte[] output = hexStringConverter.decodeUsingGuava(hexString);
assertArrayEquals(bytes, output);
}
@Test
public void shouldEncodeByteArrayToHexStringUsingApacheCommons() throws DecoderException {
byte[] bytes = getSampleBytes();
String hexString = getSampleHexString();
String output = hexStringConverter.encodeUsingApacheCommons(bytes);
assertThat(output, IsEqualIgnoringCase.equalToIgnoringCase(hexString));
}
@Test
public void shouldDecodeHexStringToByteArrayUsingApacheCommons() throws DecoderException {
byte[] bytes = getSampleBytes();
String hexString = getSampleHexString();
byte[] output = hexStringConverter.decodeUsingApacheCommons(hexString);
assertArrayEquals(bytes, output);
}
private String getSampleHexString() {
return "0af50c0e2d10";
}
private byte[] getSampleBytes() {
return new byte[] { 10, -11, 12, 14, 45, 16 };
}
}

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package com.baeldung.algorithms.distancebetweenpoints;
import org.junit.Test;
import com.baeldung.algorithms.distancebetweenpoints.DistanceBetweenPointsService;
import static org.junit.Assert.assertEquals;
public class DistanceBetweenPointsServiceUnitTest {
private DistanceBetweenPointsService service = new DistanceBetweenPointsService();
@Test
public void givenTwoPoints_whenCalculateDistanceByFormula_thenCorrect() {
double x1 = 3;
double y1 = 4;
double x2 = 7;
double y2 = 1;
double distance = service.calculateDistanceBetweenPoints(x1, y1, x2, y2);
assertEquals(distance, 5, 0.001);
}
@Test
public void givenTwoPoints_whenCalculateDistanceWithHypot_thenCorrect() {
double x1 = 3;
double y1 = 4;
double x2 = 7;
double y2 = 1;
double distance = service.calculateDistanceBetweenPointsWithHypot(x1, y1, x2, y2);
assertEquals(distance, 5, 0.001);
}
@Test
public void givenTwoPoints_whenCalculateDistanceWithPoint2D_thenCorrect() {
double x1 = 3;
double y1 = 4;
double x2 = 7;
double y2 = 1;
double distance = service.calculateDistanceBetweenPointsWithPoint2D(x1, y1, x2, y2);
assertEquals(distance, 5, 0.001);
}
}

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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 }
});
}
}

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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));
}
}

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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);
}
}

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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);
}
}

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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);
}
}

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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;
}
}

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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);
}
}

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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);
}
}

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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);
}
}

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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"));
}
}

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package com.baeldung.algorithms.rectanglesoverlap;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.assertFalse;
import org.junit.Test;
import com.baeldung.algorithms.rectanglesoverlap.Point;
import com.baeldung.algorithms.rectanglesoverlap.Rectangle;
public class RectangleUnitTest {
@Test
public void givenTwoOverlappingRectangles_whenisOverlappingCalled_shouldReturnTrue() {
Rectangle rectangle1 = new Rectangle(new Point(2, 1), new Point(4, 3));
Rectangle rectangle2 = new Rectangle(new Point(1, 1), new Point(6, 4));
assertTrue(rectangle1.isOverlapping(rectangle2));
rectangle1 = new Rectangle(new Point(-5, -2), new Point(2, 3));
rectangle2 = new Rectangle(new Point(-2, -1), new Point(5, 2));
assertTrue(rectangle1.isOverlapping(rectangle2));
rectangle1 = new Rectangle(new Point(-5, 1), new Point(2, 4));
rectangle2 = new Rectangle(new Point(-2, -2), new Point(5, 5));
assertTrue(rectangle1.isOverlapping(rectangle2));
}
@Test
public void givenTwoNonOverlappingRectangles_whenisOverlappingCalled_shouldReturnFalse() {
Rectangle rectangle1 = new Rectangle(new Point(-5, 1), new Point(-3, 4));
Rectangle rectangle2 = new Rectangle(new Point(-2, -2), new Point(5, 5));
assertFalse(rectangle1.isOverlapping(rectangle2));
rectangle1 = new Rectangle(new Point(-5, 1), new Point(3, 4));
rectangle2 = new Rectangle(new Point(-2, -2), new Point(5, -1));
assertFalse(rectangle1.isOverlapping(rectangle2));
rectangle1 = new Rectangle(new Point(-2, 1), new Point(0, 3));
rectangle2 = new Rectangle(new Point(3, 1), new Point(5, 4));
assertFalse(rectangle1.isOverlapping(rectangle2));
}
}

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package com.baeldung.algorithms.romannumerals;
import static org.assertj.core.api.Assertions.assertThat;
import org.junit.Test;
public class RomanArabicConverterUnitTest {
@Test
public void given2018Roman_WhenConvertingToArabic_ThenReturn2018() {
String roman2018 = "MMXVIII";
int result = RomanArabicConverter.romanToArabic(roman2018);
assertThat(result).isEqualTo(2018);
}
@Test
public void given1999Arabic_WhenConvertingToRoman_ThenReturnMCMXCIX() {
int arabic1999 = 1999;
String result = RomanArabicConverter.arabicToRoman(arabic1999);
assertThat(result).isEqualTo("MCMXCIX");
}
}

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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());
}
}

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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);
}
}

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package com.baeldung.jgrapht;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import java.util.stream.IntStream;
import org.jgrapht.GraphPath;
import org.jgrapht.alg.cycle.HierholzerEulerianCycle;
import org.jgrapht.graph.DefaultEdge;
import org.jgrapht.graph.SimpleWeightedGraph;
import org.junit.Before;
import org.junit.Test;
public class EulerianCircuitUnitTest {
SimpleWeightedGraph<String, DefaultEdge> simpleGraph;
@Before
public void createGraphWithEulerianCircuit() {
simpleGraph = new SimpleWeightedGraph<>(DefaultEdge.class);
IntStream.range(1, 6).forEach(i -> {
simpleGraph.addVertex("v" + i);
});
IntStream.range(1, 6).forEach(i -> {
int endVertexNo = (i + 1) > 5 ? 1 : i + 1;
simpleGraph.addEdge("v" + i, "v" + endVertexNo);
});
}
@Test
public void givenGraph_whenCheckEluerianCycle_thenGetResult() {
HierholzerEulerianCycle eulerianCycle = new HierholzerEulerianCycle<>();
assertTrue(eulerianCycle.isEulerian(simpleGraph));
}
@Test
public void givenGraphWithEulerianCircuit_whenGetEulerianCycle_thenGetGraphPath() {
HierholzerEulerianCycle eulerianCycle = new HierholzerEulerianCycle<>();
GraphPath path = eulerianCycle.getEulerianCycle(simpleGraph);
assertTrue(path.getEdgeList().containsAll(simpleGraph.edgeSet()));
}
}