Merge branch 'TheAlgorithms:master' into master

Author: electyrion

.github/workflows/build.yml

@@ -17,15 +17,15 @@ jobs:
         if: >-
           github.event_name == 'pull_request' &&
           github.event.pull_request.head.repo.full_name != github.repository
-        uses: codecov/codecov-action@v4
+        uses: codecov/codecov-action@v5
         with:
           fail_ci_if_error: true
       - name: Upload coverage to codecov (with token)
         if: >
           github.repository == 'TheAlgorithms/Java' &&
           (github.event_name != 'pull_request' ||
           github.event.pull_request.head.repo.full_name == github.repository)
-        uses: codecov/codecov-action@v4
+        uses: codecov/codecov-action@v5
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: true

.gitpod.dockerfile

@@ -1,4 +1,4 @@
-FROM gitpod/workspace-java-21:2024-09-11-00-04-27
+FROM gitpod/workspace-java-21:2024-11-26-08-43-19
 
 ENV LLVM_SCRIPT="tmp_llvm.sh"
 

pom.xml

@@ -12,15 +12,15 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>21</maven.compiler.source>
         <maven.compiler.target>21</maven.compiler.target>
-        <assertj.version>3.26.3</assertj.version>
+        <assertj.version>3.27.0</assertj.version>
     </properties>
 
     <dependencyManagement>
         <dependencies>
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>
-                <version>5.11.3</version>
+                <version>5.11.4</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>
@@ -31,7 +31,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
-            <version>5.11.3</version>
+            <version>5.11.4</version>
             <scope>test</scope>
         </dependency>
         <dependency>
@@ -51,7 +51,7 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>
-            <version>5.11.3</version>
+            <version>5.11.4</version>
             <scope>test</scope>
         </dependency>
         <dependency>
@@ -62,15 +62,15 @@
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-collections4</artifactId>
-            <version>4.5.0-M2</version>
+            <version>4.5.0-M3</version>
         </dependency>
     </dependencies>
 
     <build>
         <plugins>
             <plugin>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>3.5.1</version>
+                <version>3.5.2</version>
                 <configuration>
                     <forkNode implementation="org.apache.maven.plugin.surefire.extensions.SurefireForkNodeFactory"/>
                 </configuration>
@@ -125,22 +125,22 @@
                     <dependency>
                     <groupId>com.puppycrawl.tools</groupId>
                     <artifactId>checkstyle</artifactId>
-                    <version>10.20.0</version>
+                    <version>10.21.1</version>
                     </dependency>
                 </dependencies>
             </plugin>
             <plugin>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs-maven-plugin</artifactId>
-                <version>4.8.6.5</version>
+                <version>4.8.6.6</version>
                 <configuration>
                     <excludeFilterFile>spotbugs-exclude.xml</excludeFilterFile>
                     <includeTests>true</includeTests>
                     <plugins>
                         <plugin>
                             <groupId>com.mebigfatguy.fb-contrib</groupId>
                             <artifactId>fb-contrib</artifactId>
-                            <version>7.6.5</version>
+                            <version>7.6.9</version>
                         </plugin>
                         <plugin>
                             <groupId>com.h3xstream.findsecbugs</groupId>

src/main/java/com/thealgorithms/ciphers/AES.java

@@ -2418,8 +2418,6 @@ public static BigInteger scheduleCore(BigInteger t, int rconCounter) {
             rBytes = new StringBuilder(rBytes.substring(0, i * 2) + currentByteBits + rBytes.substring((i + 1) * 2));
         }
 
-        // t = new BigInteger(rBytes, 16);
-        // return t;
         return new BigInteger(rBytes.toString(), 16);
     }
 

src/main/java/com/thealgorithms/ciphers/AffineCipher.java

@@ -34,19 +34,19 @@ private AffineCipher() {
      */
     static String encryptMessage(char[] msg) {
         // Cipher Text initially empty
-        String cipher = "";
+        StringBuilder cipher = new StringBuilder();
         for (int i = 0; i < msg.length; i++) {
             // Avoid space to be encrypted
             /* applying encryption formula ( a * x + b ) mod m
             {here x is msg[i] and m is 26} and added 'A' to
             bring it in the range of ASCII alphabet [65-90 | A-Z] */
             if (msg[i] != ' ') {
-                cipher += (char) ((((a * (msg[i] - 'A')) + b) % 26) + 'A');
+                cipher.append((char) ((((a * (msg[i] - 'A')) + b) % 26) + 'A'));
             } else { // else simply append space character
-                cipher += msg[i];
+                cipher.append(msg[i]);
             }
         }
-        return cipher;
+        return cipher.toString();
     }
 
     /**
@@ -56,7 +56,7 @@ static String encryptMessage(char[] msg) {
      * @return the decrypted plaintext message
      */
     static String decryptCipher(String cipher) {
-        String msg = "";
+        StringBuilder msg = new StringBuilder();
         int aInv = 0;
         int flag;
 
@@ -75,13 +75,13 @@ static String decryptCipher(String cipher) {
             {here x is cipher[i] and m is 26} and added 'A'
             to bring it in the range of ASCII alphabet [65-90 | A-Z] */
             if (cipher.charAt(i) != ' ') {
-                msg += (char) (((aInv * ((cipher.charAt(i) - 'A') - b + 26)) % 26) + 'A');
+                msg.append((char) (((aInv * ((cipher.charAt(i) - 'A') - b + 26)) % 26) + 'A'));
             } else { // else simply append space character
-                msg += cipher.charAt(i);
+                msg.append(cipher.charAt(i));
             }
         }
 
-        return msg;
+        return msg.toString();
     }
 
     // Driver code

src/main/java/com/thealgorithms/ciphers/Blowfish.java

@@ -1078,7 +1078,7 @@ public class Blowfish {
      * @return String object which is a binary representation of the hex number passed as parameter
      */
     private String hexToBin(String hex) {
-        String binary = "";
+        StringBuilder binary = new StringBuilder();
         long num;
         String binary4B;
         int n = hex.length();
@@ -1089,9 +1089,9 @@ private String hexToBin(String hex) {
             binary4B = "0000" + binary4B;
 
             binary4B = binary4B.substring(binary4B.length() - 4);
-            binary += binary4B;
+            binary.append(binary4B);
         }
-        return binary;
+        return binary.toString();
     }
 
     /**
@@ -1103,12 +1103,12 @@ private String hexToBin(String hex) {
      */
     private String binToHex(String binary) {
         long num = Long.parseUnsignedLong(binary, 2);
-        String hex = Long.toHexString(num);
+        StringBuilder hex = new StringBuilder(Long.toHexString(num));
         while (hex.length() < (binary.length() / 4)) {
-            hex = "0" + hex;
+            hex.insert(0, "0");
         }
 
-        return hex;
+        return hex.toString();
     }
 
     /**
@@ -1121,12 +1121,12 @@ private String binToHex(String binary) {
     private String xor(String a, String b) {
         a = hexToBin(a);
         b = hexToBin(b);
-        String ans = "";
+        StringBuilder ans = new StringBuilder();
         for (int i = 0; i < a.length(); i++) {
-            ans += (char) (((a.charAt(i) - '0') ^ (b.charAt(i) - '0')) + '0');
+            ans.append((char) (((a.charAt(i) - '0') ^ (b.charAt(i) - '0')) + '0'));
         }
-        ans = binToHex(ans);
-        return ans;
+        ans = new StringBuilder(binToHex(ans.toString()));
+        return ans.toString();
     }
 
     /**

src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java

@@ -136,7 +136,7 @@ public static String base2base(String n, int b1, int b2) {
         int decimalValue = 0;
         int charB2;
         char charB1;
-        String output = "";
+        StringBuilder output = new StringBuilder();
         // Go through every character of n
         for (int i = 0; i < n.length(); i++) {
             // store the character in charB1
@@ -167,15 +167,15 @@ public static String base2base(String n, int b1, int b2) {
             // If the remainder is a digit < 10, simply add it to
             // the left side of the new number.
             if (decimalValue % b2 < 10) {
-                output = decimalValue % b2 + output;
+                output.insert(0, decimalValue % b2);
             } // If the remainder is >= 10, add a character with the
             // corresponding value to the new number. (A = 10, B = 11, C = 12, ...)
             else {
-                output = (char) ((decimalValue % b2) + 55) + output;
+                output.insert(0, (char) ((decimalValue % b2) + 55));
             }
             // Divide by the new base again
             decimalValue /= b2;
         }
-        return output;
+        return output.toString();
     }
 }

src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java

@@ -52,9 +52,11 @@ public String convert(String numHex) {
      */
     public String completeDigits(String binNum) {
         final int byteSize = 8;
-        while (binNum.length() < byteSize) {
-            binNum = "0" + binNum;
+        StringBuilder binNumBuilder = new StringBuilder(binNum);
+        while (binNumBuilder.length() < byteSize) {
+            binNumBuilder.insert(0, "0");
         }
+        binNum = binNumBuilder.toString();
         return binNum;
     }
 }

src/main/java/com/thealgorithms/datastructures/graphs/DijkstraOptimizedAlgorithm.java

@@ -0,0 +1,66 @@
+package com.thealgorithms.datastructures.graphs;
+
+import java.util.Arrays;
+import java.util.Set;
+import java.util.TreeSet;
+import org.apache.commons.lang3.tuple.Pair;
+
+/**
+ * Dijkstra's algorithm for finding the shortest path from a single source vertex to all other vertices in a graph.
+ */
+public class DijkstraOptimizedAlgorithm {
+
+    private final int vertexCount;
+
+    /**
+     * Constructs a Dijkstra object with the given number of vertices.
+     *
+     * @param vertexCount The number of vertices in the graph.
+     */
+    public DijkstraOptimizedAlgorithm(int vertexCount) {
+        this.vertexCount = vertexCount;
+    }
+
+    /**
+     * Executes Dijkstra's algorithm on the provided graph to find the shortest paths from the source vertex to all other vertices.
+     *
+     * The graph is represented as an adjacency matrix where {@code graph[i][j]} represents the weight of the edge from vertex {@code i}
+     * to vertex {@code j}. A value of 0 indicates no edge exists between the vertices.
+     *
+     * @param graph The graph represented as an adjacency matrix.
+     * @param source The source vertex.
+     * @return An array where the value at each index {@code i} represents the shortest distance from the source vertex to vertex {@code i}.
+     * @throws IllegalArgumentException if the source vertex is out of range.
+     */
+    public int[] run(int[][] graph, int source) {
+        if (source < 0 || source >= vertexCount) {
+            throw new IllegalArgumentException("Incorrect source");
+        }
+
+        int[] distances = new int[vertexCount];
+        boolean[] processed = new boolean[vertexCount];
+        Set<Pair<Integer, Integer>> unprocessed = new TreeSet<>();
+
+        Arrays.fill(distances, Integer.MAX_VALUE);
+        Arrays.fill(processed, false);
+        distances[source] = 0;
+        unprocessed.add(Pair.of(0, source));
+
+        while (!unprocessed.isEmpty()) {
+            Pair<Integer, Integer> distanceAndU = unprocessed.iterator().next();
+            unprocessed.remove(distanceAndU);
+            int u = distanceAndU.getRight();
+            processed[u] = true;
+
+            for (int v = 0; v < vertexCount; v++) {
+                if (!processed[v] && graph[u][v] != 0 && distances[u] != Integer.MAX_VALUE && distances[u] + graph[u][v] < distances[v]) {
+                    unprocessed.remove(Pair.of(distances[v], v));
+                    distances[v] = distances[u] + graph[u][v];
+                    unprocessed.add(Pair.of(distances[v], v));
+                }
+            }
+        }
+
+        return distances;
+    }
+}

src/main/java/com/thealgorithms/datastructures/graphs/FloydWarshall.java

@@ -42,9 +42,7 @@ public FloydWarshall(int numberofvertices) {
     public void floydwarshall(int[][] adjacencyMatrix) {
         // Initialize the distance matrix with the adjacency matrix.
         for (int source = 1; source <= numberofvertices; source++) {
-            for (int destination = 1; destination <= numberofvertices; destination++) {
-                distanceMatrix[source][destination] = adjacencyMatrix[source][destination];
-            }
+            System.arraycopy(adjacencyMatrix[source], 1, distanceMatrix[source], 1, numberofvertices);
         }
         for (int intermediate = 1; intermediate <= numberofvertices; intermediate++) {
             for (int source = 1; source <= numberofvertices; source++) {