Merge remote-tracking branch 'upstream/master'

This commit is contained in:
Roger Yates
2019-12-08 22:05:44 +10:00
3012 changed files with 25159 additions and 160991 deletions
+41 -42
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@@ -1,47 +1,46 @@
<?xml version="1.0"?>
<project
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<?xml version="1.0" encoding="UTF-8"?>
<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<modelVersion>4.0.0</modelVersion>
<artifactId>akka-http</artifactId>
<name>akka-http</name>
<modelVersion>4.0.0</modelVersion>
<artifactId>akka-http</artifactId>
<name>akka-http</name>
<parent>
<groupId>com.baeldung</groupId>
<artifactId>parent-modules</artifactId>
<version>1.0.0-SNAPSHOT</version>
</parent>
<parent>
<artifactId>parent-modules</artifactId>
<groupId>com.baeldung</groupId>
<version>1.0.0-SNAPSHOT</version>
</parent>
<dependencies>
<dependency>
<groupId>com.typesafe.akka</groupId>
<artifactId>akka-http_2.12</artifactId>
<version>${akka.http.version}</version>
</dependency>
<dependency>
<groupId>com.typesafe.akka</groupId>
<artifactId>akka-stream_2.12</artifactId>
<version>${akka.stream.version}</version>
</dependency>
<dependency>
<groupId>com.typesafe.akka</groupId>
<artifactId>akka-http-jackson_2.12</artifactId>
<version>${akka.http.version}</version>
</dependency>
<dependency>
<groupId>com.typesafe.akka</groupId>
<artifactId>akka-http-testkit_2.12</artifactId>
<version>${akka.http.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
<dependencies>
<dependency>
<groupId>com.typesafe.akka</groupId>
<artifactId>akka-http_2.12</artifactId>
<version>${akka.http.version}</version>
</dependency>
<dependency>
<groupId>com.typesafe.akka</groupId>
<artifactId>akka-stream_2.12</artifactId>
<version>${akka.stream.version}</version>
</dependency>
<dependency>
<groupId>com.typesafe.akka</groupId>
<artifactId>akka-http-jackson_2.12</artifactId>
<version>${akka.http.version}</version>
</dependency>
<dependency>
<groupId>com.typesafe.akka</groupId>
<artifactId>akka-http-testkit_2.12</artifactId>
<version>${akka.http.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<akka.http.version>10.0.11</akka.http.version>
<akka.stream.version>2.5.11</akka.stream.version>
</properties>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<akka.http.version>10.0.11</akka.http.version>
<akka.stream.version>2.5.11</akka.stream.version>
</properties>
</project>
+2 -2
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@@ -1,13 +1,13 @@
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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>akka-streams</artifactId>
<name>akka-streams</name>
<parent>
<artifactId>parent-modules</artifactId>
<groupId>com.baeldung</groupId>
<artifactId>parent-modules</artifactId>
<version>1.0.0-SNAPSHOT</version>
</parent>
+3 -3
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@@ -1,10 +1,11 @@
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>algorithms-genetic</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>algorithms-genetic</name>
<parent>
<groupId>com.baeldung</groupId>
<artifactId>parent-modules</artifactId>
@@ -60,5 +61,4 @@
<commons-codec.version>1.11</commons-codec.version>
</properties>
</project>
-2
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@@ -7,8 +7,6 @@ This module contains articles about algorithms. Some classes of algorithms, e.g.
- [Validating Input With Finite Automata in Java](https://www.baeldung.com/java-finite-automata)
- [Example of Hill Climbing Algorithm](https://www.baeldung.com/java-hill-climbing-algorithm)
- [Monte Carlo Tree Search for Tic-Tac-Toe Game](https://www.baeldung.com/java-monte-carlo-tree-search)
- [Binary Search Algorithm in Java](https://www.baeldung.com/java-binary-search)
- [Introduction to Minimax Algorithm](https://www.baeldung.com/java-minimax-algorithm)
- [How to Calculate Levenshtein Distance in Java?](https://www.baeldung.com/java-levenshtein-distance)
- [How to Find the Kth Largest Element in Java](https://www.baeldung.com/java-kth-largest-element)
+4 -3
View File
@@ -1,10 +1,11 @@
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>algorithms-miscellaneous-1</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>algorithms-miscellaneous-1</name>
<parent>
<groupId>com.baeldung</groupId>
<artifactId>parent-modules</artifactId>
@@ -43,7 +44,7 @@
<groupId>com.github.dpaukov</groupId>
<artifactId>combinatoricslib3</artifactId>
<version>${combinatoricslib3.version}</version>
</dependency>
</dependency>
</dependencies>
<build>
+5 -4
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@@ -1,5 +1,6 @@
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>algorithms-miscellaneous-2</artifactId>
<version>0.0.1-SNAPSHOT</version>
@@ -34,9 +35,9 @@
<version>${org.jgrapht.core.version}</version>
</dependency>
<dependency>
<groupId>org.jgrapht</groupId>
<artifactId>jgrapht-ext</artifactId>
<version>${org.jgrapht.ext.version}</version>
<groupId>org.jgrapht</groupId>
<artifactId>jgrapht-ext</artifactId>
<version>${org.jgrapht.ext.version}</version>
</dependency>
<dependency>
<groupId>pl.allegro.finance</groupId>
@@ -0,0 +1,30 @@
package com.baeldung.algorithms.astar;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;
public class Graph<T extends GraphNode> {
private final Set<T> nodes;
private final Map<String, Set<String>> connections;
public Graph(Set<T> nodes, Map<String, Set<String>> connections) {
this.nodes = nodes;
this.connections = connections;
}
public T getNode(String id) {
return nodes.stream()
.filter(node -> node.getId().equals(id))
.findFirst()
.orElseThrow(() -> new IllegalArgumentException("No node found with ID"));
}
public Set<T> getConnections(T node) {
return connections.get(node.getId()).stream()
.map(this::getNode)
.collect(Collectors.toSet());
}
}
@@ -0,0 +1,5 @@
package com.baeldung.algorithms.astar;
public interface GraphNode {
String getId();
}
@@ -0,0 +1,66 @@
package com.baeldung.algorithms.astar;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.PriorityQueue;
import java.util.Queue;
import java.util.stream.Collectors;
public class RouteFinder<T extends GraphNode> {
private final Graph<T> graph;
private final Scorer<T> nextNodeScorer;
private final Scorer<T> targetScorer;
public RouteFinder(Graph<T> graph, Scorer<T> nextNodeScorer, Scorer<T> targetScorer) {
this.graph = graph;
this.nextNodeScorer = nextNodeScorer;
this.targetScorer = targetScorer;
}
public List<T> findRoute(T from, T to) {
Map<T, RouteNode<T>> allNodes = new HashMap<>();
Queue<RouteNode> openSet = new PriorityQueue<>();
RouteNode<T> start = new RouteNode<>(from, null, 0d, targetScorer.computeCost(from, to));
allNodes.put(from, start);
openSet.add(start);
while (!openSet.isEmpty()) {
System.out.println("Open Set contains: " + openSet.stream().map(RouteNode::getCurrent).collect(Collectors.toSet()));
RouteNode<T> next = openSet.poll();
System.out.println("Looking at node: " + next);
if (next.getCurrent().equals(to)) {
System.out.println("Found our destination!");
List<T> route = new ArrayList<>();
RouteNode<T> current = next;
do {
route.add(0, current.getCurrent());
current = allNodes.get(current.getPrevious());
} while (current != null);
System.out.println("Route: " + route);
return route;
}
graph.getConnections(next.getCurrent()).forEach(connection -> {
double newScore = next.getRouteScore() + nextNodeScorer.computeCost(next.getCurrent(), connection);
RouteNode<T> nextNode = allNodes.getOrDefault(connection, new RouteNode<>(connection));
allNodes.put(connection, nextNode);
if (nextNode.getRouteScore() > newScore) {
nextNode.setPrevious(next.getCurrent());
nextNode.setRouteScore(newScore);
nextNode.setEstimatedScore(newScore + targetScorer.computeCost(connection, to));
openSet.add(nextNode);
System.out.println("Found a better route to node: " + nextNode);
}
});
}
throw new IllegalStateException("No route found");
}
}
@@ -0,0 +1,67 @@
package com.baeldung.algorithms.astar;
import java.util.StringJoiner;
class RouteNode<T extends GraphNode> implements Comparable<RouteNode> {
private final T current;
private T previous;
private double routeScore;
private double estimatedScore;
RouteNode(T current) {
this(current, null, Double.POSITIVE_INFINITY, Double.POSITIVE_INFINITY);
}
RouteNode(T current, T previous, double routeScore, double estimatedScore) {
this.current = current;
this.previous = previous;
this.routeScore = routeScore;
this.estimatedScore = estimatedScore;
}
T getCurrent() {
return current;
}
T getPrevious() {
return previous;
}
double getRouteScore() {
return routeScore;
}
double getEstimatedScore() {
return estimatedScore;
}
void setPrevious(T previous) {
this.previous = previous;
}
void setRouteScore(double routeScore) {
this.routeScore = routeScore;
}
void setEstimatedScore(double estimatedScore) {
this.estimatedScore = estimatedScore;
}
@Override
public int compareTo(RouteNode other) {
if (this.estimatedScore > other.estimatedScore) {
return 1;
} else if (this.estimatedScore < other.estimatedScore) {
return -1;
} else {
return 0;
}
}
@Override
public String toString() {
return new StringJoiner(", ", RouteNode.class.getSimpleName() + "[", "]").add("current=" + current)
.add("previous=" + previous).add("routeScore=" + routeScore).add("estimatedScore=" + estimatedScore)
.toString();
}
}
@@ -0,0 +1,5 @@
package com.baeldung.algorithms.astar;
public interface Scorer<T extends GraphNode> {
double computeCost(T from, T to);
}
@@ -0,0 +1,19 @@
package com.baeldung.algorithms.astar.underground;
import com.baeldung.algorithms.astar.Scorer;
public class HaversineScorer implements Scorer<Station> {
@Override
public double computeCost(Station from, Station to) {
double R = 6372.8; // In kilometers
double dLat = Math.toRadians(to.getLatitude() - from.getLatitude());
double dLon = Math.toRadians(to.getLongitude() - from.getLongitude());
double lat1 = Math.toRadians(from.getLatitude());
double lat2 = Math.toRadians(to.getLatitude());
double a = Math.pow(Math.sin(dLat / 2),2) + Math.pow(Math.sin(dLon / 2),2) * Math.cos(lat1) * Math.cos(lat2);
double c = 2 * Math.asin(Math.sqrt(a));
return R * c;
}
}
@@ -0,0 +1,42 @@
package com.baeldung.algorithms.astar.underground;
import java.util.StringJoiner;
import com.baeldung.algorithms.astar.GraphNode;
public class Station implements GraphNode {
private final String id;
private final String name;
private final double latitude;
private final double longitude;
public Station(String id, String name, double latitude, double longitude) {
this.id = id;
this.name = name;
this.latitude = latitude;
this.longitude = longitude;
}
@Override
public String getId() {
return id;
}
public String getName() {
return name;
}
public double getLatitude() {
return latitude;
}
public double getLongitude() {
return longitude;
}
@Override
public String toString() {
return new StringJoiner(", ", Station.class.getSimpleName() + "[", "]").add("id='" + id + "'")
.add("name='" + name + "'").add("latitude=" + latitude).add("longitude=" + longitude).toString();
}
}
-2
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@@ -14,8 +14,6 @@ This module contains articles about algorithms. Some classes of algorithms, e.g.
- [A Guide to the Folding Technique in Java](https://www.baeldung.com/folding-hashing-technique)
- [Creating a Triangle with for Loops in Java](https://www.baeldung.com/java-print-triangle)
- [Efficient Word Frequency Calculator in Java](https://www.baeldung.com/java-word-frequency)
- [Interpolation Search in Java](https://www.baeldung.com/java-interpolation-search)
- [The K-Means Clustering Algorithm in Java](https://www.baeldung.com/java-k-means-clustering-algorithm)
- [Creating a Custom Annotation in Java](https://www.baeldung.com/java-custom-annotation)
- [Breadth-First Search Algorithm in Java](https://www.baeldung.com/java-breadth-first-search)
- More articles: [[<-- prev]](/algorithms-miscellaneous-2) [[next -->]](/algorithms-miscellaneous-4)
+2
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@@ -1,3 +1,4 @@
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
@@ -91,4 +92,5 @@
<jmh-core.version>1.19</jmh-core.version>
<jmh-generator.version>1.19</jmh-generator.version>
</properties>
</project>
+1 -1
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@@ -5,10 +5,10 @@ This module contains articles about algorithms. Some classes of algorithms, e.g.
### Relevant articles:
- [Multi-Swarm Optimization Algorithm in Java](https://www.baeldung.com/java-multi-swarm-algorithm)
- [String Search Algorithms for Large Texts](https://www.baeldung.com/java-full-text-search-algorithms)
- [Check If a String Contains All The Letters of The Alphabet](https://www.baeldung.com/java-string-contains-all-letters)
- [Find the Middle Element of a Linked List](https://www.baeldung.com/java-linked-list-middle-element)
- [Find Substrings That Are Palindromes in Java](https://www.baeldung.com/java-palindrome-substrings)
- [Find the Longest Substring without Repeating Characters](https://www.baeldung.com/java-longest-substring-without-repeated-characters)
- [Permutations of an Array in Java](https://www.baeldung.com/java-array-permutations)
- [Find the Smallest Missing Integer in an Array](https://www.baeldung.com/java-smallest-missing-integer-in-array)
- More articles: [[<-- prev]](/algorithms-miscellaneous-3) [[next -->]](/algorithms-miscellaneous-5)
+3 -2
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@@ -1,10 +1,11 @@
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>algorithms-miscellaneous-4</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>algorithms-miscellaneous-4</name>
<parent>
<groupId>com.baeldung</groupId>
<artifactId>parent-modules</artifactId>
@@ -1,25 +0,0 @@
package com.baeldung.algorithms;
import org.junit.Assert;
import org.junit.Test;
import com.baeldung.algorithms.string.search.StringSearchAlgorithms;
public class StringSearchAlgorithmsUnitTest {
@Test
public void testStringSearchAlgorithms(){
String text = "This is some nice text.";
String pattern = "some";
int realPosition = text.indexOf(pattern);
Assert.assertTrue(realPosition == StringSearchAlgorithms.simpleTextSearch(pattern.toCharArray(), text.toCharArray()));
Assert.assertTrue(realPosition == StringSearchAlgorithms.RabinKarpMethod(pattern.toCharArray(), text.toCharArray()));
Assert.assertTrue(realPosition == StringSearchAlgorithms.KnuthMorrisPrattSearch(pattern.toCharArray(), text.toCharArray()));
Assert.assertTrue(realPosition == StringSearchAlgorithms.BoyerMooreHorspoolSimpleSearch(pattern.toCharArray(), text.toCharArray()));
Assert.assertTrue(realPosition == StringSearchAlgorithms.BoyerMooreHorspoolSearch(pattern.toCharArray(), text.toCharArray()));
}
}
@@ -85,4 +85,13 @@ class SmallestMissingPositiveIntegerUnitTest {
assertThat(result).isEqualTo(input.length);
}
@Test
void givenArrayWithoutZero_whenSearchInUnsortedArrayBooleanArray_thenZero() {
int[] input = new int[] {11, 13, 14, 15};
int result = SmallestMissingPositiveInteger.searchInUnsortedArrayBooleanArray(input);
assertThat(result).isEqualTo(0);
}
}
+1
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@@ -9,4 +9,5 @@ This module contains articles about algorithms. Some classes of algorithms, e.g.
- [Reversing a Binary Tree in Java](https://www.baeldung.com/java-reversing-a-binary-tree)
- [Find If Two Numbers Are Relatively Prime in Java](https://www.baeldung.com/java-two-relatively-prime-numbers)
- [Knapsack Problem Implementation in Java](https://www.baeldung.com/java-knapsack)
- [How to Determine if a Binary Tree is Balanced](https://www.baeldung.com/java-balanced-binary-tree)
- More articles: [[<-- prev]](/../algorithms-miscellaneous-4)
+9 -1
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@@ -1,5 +1,6 @@
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>algorithms-miscellaneous-5</artifactId>
<version>0.0.1-SNAPSHOT</version>
@@ -17,6 +18,11 @@
<artifactId>commons-codec</artifactId>
<version>${commons-codec.version}</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-math3</artifactId>
<version>${commons-math3.version}</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
@@ -28,6 +34,7 @@
<artifactId>tradukisto</artifactId>
<version>${tradukisto.version}</version>
</dependency>
<dependency>
<groupId>org.assertj</groupId>
<artifactId>assertj-core</artifactId>
@@ -52,6 +59,7 @@
<tradukisto.version>1.0.1</tradukisto.version>
<org.assertj.core.version>3.9.0</org.assertj.core.version>
<commons-codec.version>1.11</commons-codec.version>
<commons-math3.version>3.6.1</commons-math3.version>
</properties>
</project>
@@ -0,0 +1,83 @@
package com.baeldung.algorithms.caesarcipher;
import org.apache.commons.math3.stat.inference.ChiSquareTest;
import java.util.Arrays;
import java.util.stream.IntStream;
public class CaesarCipher {
private static final char LETTER_A = 'a';
private static final char LETTER_Z = 'z';
private static final int ALPHABET_SIZE = LETTER_Z - LETTER_A + 1;
private static final double[] ENGLISH_LETTERS_PROBABILITIES = {0.073, 0.009, 0.030, 0.044, 0.130, 0.028, 0.016, 0.035, 0.074, 0.002, 0.003, 0.035, 0.025, 0.078, 0.074, 0.027, 0.003, 0.077, 0.063, 0.093, 0.027, 0.013, 0.016, 0.005, 0.019, 0.001};
public String cipher(String message, int offset) {
StringBuilder result = new StringBuilder();
for (char character : message.toCharArray()) {
if (character != ' ') {
int originalAlphabetPosition = character - LETTER_A;
int newAlphabetPosition = (originalAlphabetPosition + offset) % ALPHABET_SIZE;
char newCharacter = (char) (LETTER_A + newAlphabetPosition);
result.append(newCharacter);
} else {
result.append(character);
}
}
return result.toString();
}
public String decipher(String message, int offset) {
return cipher(message, ALPHABET_SIZE - (offset % ALPHABET_SIZE));
}
public int breakCipher(String message) {
return probableOffset(chiSquares(message));
}
private double[] chiSquares(String message) {
double[] expectedLettersFrequencies = expectedLettersFrequencies(message.length());
double[] chiSquares = new double[ALPHABET_SIZE];
for (int offset = 0; offset < chiSquares.length; offset++) {
String decipheredMessage = decipher(message, offset);
long[] lettersFrequencies = observedLettersFrequencies(decipheredMessage);
double chiSquare = new ChiSquareTest().chiSquare(expectedLettersFrequencies, lettersFrequencies);
chiSquares[offset] = chiSquare;
}
return chiSquares;
}
private long[] observedLettersFrequencies(String message) {
return IntStream.rangeClosed(LETTER_A, LETTER_Z)
.mapToLong(letter -> countLetter((char) letter, message))
.toArray();
}
private long countLetter(char letter, String message) {
return message.chars()
.filter(character -> character == letter)
.count();
}
private double[] expectedLettersFrequencies(int messageLength) {
return Arrays.stream(ENGLISH_LETTERS_PROBABILITIES)
.map(probability -> probability * messageLength)
.toArray();
}
private int probableOffset(double[] chiSquares) {
int probableOffset = 0;
for (int offset = 0; offset < chiSquares.length; offset++) {
System.out.println(String.format("Chi-Square for offset %d: %.2f", offset, chiSquares[offset]));
if (chiSquares[offset] < chiSquares[probableOffset]) {
probableOffset = offset;
}
}
return probableOffset;
}
}
@@ -0,0 +1,67 @@
package com.baeldung.algorithms.combinatorics;
import java.util.*;
import static java.util.Collections.swap;
public class Combinatorics {
public static List<List<Integer>> permutations(List<Integer> sequence) {
List<List<Integer>> results = new ArrayList<>();
permutationsInternal(sequence, results, 0);
return results;
}
private static void permutationsInternal(List<Integer> sequence, List<List<Integer>> results, int index) {
if (index == sequence.size() - 1) {
results.add(new ArrayList<>(sequence));
}
for (int i = index; i < sequence.size(); i++) {
swap(sequence, i, index);
permutationsInternal(sequence, results, index + 1);
swap(sequence, i, index);
}
}
public static List<List<Integer>> combinations(List<Integer> inputSet, int k) {
List<List<Integer>> results = new ArrayList<>();
combinationsInternal(inputSet, k, results, new ArrayList<>(), 0);
return results;
}
private static void combinationsInternal(
List<Integer> inputSet, int k, List<List<Integer>> results, ArrayList<Integer> accumulator, int index) {
int leftToAccumulate = k - accumulator.size();
int possibleToAcculumate = inputSet.size() - index;
if (accumulator.size() == k) {
results.add(new ArrayList<>(accumulator));
} else if (leftToAccumulate <= possibleToAcculumate) {
combinationsInternal(inputSet, k, results, accumulator, index + 1);
accumulator.add(inputSet.get(index));
combinationsInternal(inputSet, k, results, accumulator, index + 1);
accumulator.remove(accumulator.size() - 1);
}
}
public static List<List<Character>> powerSet(List<Character> sequence) {
List<List<Character>> results = new ArrayList<>();
powerSetInternal(sequence, results, new ArrayList<>(), 0);
return results;
}
private static void powerSetInternal(
List<Character> set, List<List<Character>> powerSet, List<Character> accumulator, int index) {
if (index == set.size()) {
powerSet.add(new ArrayList<>(accumulator));
} else {
accumulator.add(set.get(index));
powerSetInternal(set, powerSet, accumulator, index + 1);
accumulator.remove(accumulator.size() - 1);
powerSetInternal(set, powerSet, accumulator, index + 1);
}
}
}
@@ -0,0 +1,83 @@
package com.baeldung.algorithms.caesarcipher;
import org.junit.jupiter.api.Test;
import static org.assertj.core.api.Assertions.assertThat;
class CaesarCipherUnitTest {
private static final String SENTENCE = "he told me i could never teach a llama to drive";
private static final String SENTENCE_SHIFTED_THREE = "kh wrog ph l frxog qhyhu whdfk d oodpd wr gulyh";
private static final String SENTENCE_SHIFTED_TEN = "ro dyvn wo s myevn xofob dokmr k vvkwk dy nbsfo";
private CaesarCipher algorithm = new CaesarCipher();
@Test
void givenSentenceAndShiftThree_whenCipher_thenCipheredMessageWithoutOverflow() {
String cipheredSentence = algorithm.cipher(SENTENCE, 3);
assertThat(cipheredSentence)
.isEqualTo(SENTENCE_SHIFTED_THREE);
}
@Test
void givenSentenceAndShiftTen_whenCipher_thenCipheredMessageWithOverflow() {
String cipheredSentence = algorithm.cipher(SENTENCE, 10);
assertThat(cipheredSentence)
.isEqualTo(SENTENCE_SHIFTED_TEN);
}
@Test
void givenSentenceAndShiftThirtySix_whenCipher_thenCipheredLikeTenMessageWithOverflow() {
String cipheredSentence = algorithm.cipher(SENTENCE, 36);
assertThat(cipheredSentence)
.isEqualTo(SENTENCE_SHIFTED_TEN);
}
@Test
void givenSentenceShiftedThreeAndShiftThree_whenDecipher_thenOriginalSentenceWithoutOverflow() {
String decipheredSentence = algorithm.decipher(SENTENCE_SHIFTED_THREE, 3);
assertThat(decipheredSentence)
.isEqualTo(SENTENCE);
}
@Test
void givenSentenceShiftedTenAndShiftTen_whenDecipher_thenOriginalSentenceWithOverflow() {
String decipheredSentence = algorithm.decipher(SENTENCE_SHIFTED_TEN, 10);
assertThat(decipheredSentence)
.isEqualTo(SENTENCE);
}
@Test
void givenSentenceShiftedTenAndShiftThirtySix_whenDecipher_thenOriginalSentenceWithOverflow() {
String decipheredSentence = algorithm.decipher(SENTENCE_SHIFTED_TEN, 36);
assertThat(decipheredSentence)
.isEqualTo(SENTENCE);
}
@Test
void givenSentenceShiftedThree_whenBreakCipher_thenOriginalSentence() {
int offset = algorithm.breakCipher(SENTENCE_SHIFTED_THREE);
assertThat(offset)
.isEqualTo(3);
assertThat(algorithm.decipher(SENTENCE_SHIFTED_THREE, offset))
.isEqualTo(SENTENCE);
}
@Test
void givenSentenceShiftedTen_whenBreakCipher_thenOriginalSentence() {
int offset = algorithm.breakCipher(SENTENCE_SHIFTED_TEN);
assertThat(offset)
.isEqualTo(10);
assertThat(algorithm.decipher(SENTENCE_SHIFTED_TEN, offset))
.isEqualTo(SENTENCE);
}
}
@@ -0,0 +1,80 @@
package com.baeldung.algorithms.combinatorics;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import org.junit.Test;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertSame;
public class CombinatoricsUnitTest {
@Test
public void givenEmptySequence_whenCallingPermutations_ShouldReturnEmptyList() {
List<Integer> sequence = Arrays.asList();
List<List<Integer>> permutations = Combinatorics.permutations(sequence);
assertEquals(0, permutations.size());
}
@Test
public void givenOneElementSequence_whenCallingPermutations_ShouldReturnPermutations() {
List<Integer> sequence = Arrays.asList(1);
List<List<Integer>> permutations = Combinatorics.permutations(sequence);
assertEquals(1, permutations.size());
assertEquals(1, permutations.get(0).size());
assertSame(1, permutations.get(0).get(0));
}
@Test
public void givenFourElementsSequence_whenCallingPermutations_ShouldReturnPermutations() {
List<Integer> sequence = Arrays.asList(1, 2, 3, 4);
List<List<Integer>> permutations = Combinatorics.permutations(sequence);
assertEquals(24, permutations.size());
assertEquals(24, new HashSet<>(permutations).size());
}
@Test
public void givenTwoElements_whenCalling3Combinations_ShouldReturnEmptyList() {
List<Integer> set = Arrays.asList(1, 2);
List<List<Integer>> combinations = Combinatorics.combinations(set, 3);
assertEquals(0, combinations.size());
}
@Test
public void givenThreeElements_whenCalling3Combinations_ShouldReturnOneCombination() {
List<Integer> set = Arrays.asList(1, 2, 3);
List<List<Integer>> combinations = Combinatorics.combinations(set, 3);
assertEquals(1, combinations.size());
assertEquals(combinations.get(0), Arrays.asList(1, 2, 3));
}
@Test
public void givenFourElements_whenCalling2Combinations_ShouldReturnCombinations() {
List<Integer> set = Arrays.asList(1, 2, 3, 4);
List<List<Integer>> combinations = Combinatorics.combinations(set, 2);
assertEquals(6, combinations.size());
assertEquals(6, new HashSet<>(combinations).size());
}
@Test
public void givenFourElements_whenCallingPowerSet_ShouldReturn15Sets() {
List<Character> sequence = Arrays.asList('a', 'b', 'c', 'd');
List<List<Character>> combinations = Combinatorics.powerSet(sequence);
assertEquals(16, combinations.size());
}
}
+11
View File
@@ -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)
+38
View File
@@ -0,0 +1,38 @@
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>algorithms-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>
@@ -1,55 +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;
}
}
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;
}
}

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