feat: new recursion algo added

Author: Tuhinm2002

src/main/java/com/thealgorithms/Recursion/GenerateSubsets.java

@@ -5,6 +5,11 @@
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Finds all permutations of given array
+ * @author Tuhin Mondal (<a href="https://github.com/tuhinm2002">Git-Tuhin Mondal</a>)
+ */
+
 public final class GenerateSubsets {
 
     private GenerateSubsets() {
@@ -33,4 +38,4 @@ private static List<String> doRecursion(String p, String up) {
 
         return left;
     }
-}
+}

src/main/java/com/thealgorithms/Recursion/GenerateUniqueSubsets.java

@@ -0,0 +1,43 @@
+package com.thealgorithms.Recursion;
+
+// program to find unique power set of a string
+
+import java.util.*;
+
+/**
+ * Finds all permutations of given array
+ * @author Tuhin Mondal (<a href="https://github.com/tuhinm2002">Git-Tuhin Mondal</a>)
+ */
+
+public final class GenerateUniqueSubsets {
+
+    private GenerateUniqueSubsets() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    public static List<String> subsetRecursion(String str) {
+        Set<String> ans = doRecursion("", str);
+        List<String> a = new ArrayList<>(ans.stream().toList());
+        Collections.sort(a);
+        return a;
+    }
+
+    private static Set<String> doRecursion(String p, String up) {
+        if (up.isEmpty()) {
+            Set<String> list = new HashSet<>();
+            list.add(p);
+            return list;
+        }
+
+        // Taking the character
+        char ch = up.charAt(0);
+        // Adding the character in the recursion
+        Set<String> left = doRecursion(p + ch, up.substring(1));
+        // Not adding the character in the recursion
+        Set<String> right = doRecursion(p, up.substring(1));
+
+        left.addAll(right);
+
+        return left;
+    }
+}

src/main/java/com/thealgorithms/Recursion/TowerOfHanoi.java

@@ -0,0 +1,32 @@
+package com.thealgorithms.Recursion;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Finds all permutations of given array
+ * @author Tuhin Mondal (<a href="https://github.com/tuhinm2002">Git-Tuhin Mondal</a>)
+ */
+
+public final class TowerOfHanoi {
+    private TowerOfHanoi() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    public static List<String> towerOfHanoi(int n) {
+        List<String> arr = new ArrayList<>();
+        recursionApproach(n, 'A', 'B', 'C', arr);
+        return arr;
+    }
+
+    public static void recursionApproach(int n, char a, char b, char c, List<String> list) {
+        if (n == 1) {
+            list.add("Take disk 1 from rod " + a + " to rod " + b);
+            return;
+        }
+
+        recursionApproach(n - 1, a, c, b, list);
+        list.add("Take disk " + n + " from rod " + a + " to rod " + b);
+        recursionApproach(n - 1, c, b, a, list);
+    }
+}

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

@@ -32,7 +32,7 @@ public void setKey(String key) {
         this.key = key;
     }
 
-    // Permutation table to convert initial 64-bit key to 56 bit key
+    // GeneratePermutations table to convert initial 64-bit key to 56 bit key
     private static final int[] PC1 = {57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18, 10, 2, 59, 51, 43, 35, 27, 19, 11, 3, 60, 52, 44, 36, 63, 55, 47, 39, 31, 23, 15, 7, 62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20, 12, 4};
 
     // Lookup table used to shift the initial key, in order to generate the subkeys
@@ -66,7 +66,7 @@ public void setKey(String key) {
 
     private static final int[][][] S = {S1, S2, S3, S4, S5, S6, S7, S8};
 
-    // Permutation table, used in the Feistel function post s-box usage
+    // GeneratePermutations table, used in the Feistel function post s-box usage
     static final int[] PERMUTATION = {16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5, 18, 31, 10, 2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4, 25};
 
     // Table used for final inversion of the message box after 16 rounds of Feistel Function

src/main/java/com/thealgorithms/datastructures/crdt/GSet.java

@@ -44,10 +44,10 @@ public boolean lookup(T e) {
     }
 
     /**
-     * Compares the G-Set with another G-Set to check if it is a subset.
+     * Compares the G-Set with another G-Set to check if it is a subsetRecursion.
      *
      * @param other the other G-Set to compare with
-     * @return true if the current G-Set is a subset of the other, false otherwise
+     * @return true if the current G-Set is a subsetRecursion of the other, false otherwise
      */
     public boolean compare(GSet<T> other) {
         return other.elements.containsAll(elements);

src/main/java/com/thealgorithms/datastructures/crdt/LWWElementSet.java

@@ -88,10 +88,10 @@ public boolean lookup(Element e) {
     }
 
     /**
-     * Compares the LWWElementSet with another LWWElementSet to check if addSet and removeSet are a subset.
+     * Compares the LWWElementSet with another LWWElementSet to check if addSet and removeSet are a subsetRecursion.
      *
      * @param other The LWWElementSet to compare.
-     * @return True if the set is subset, false otherwise.
+     * @return True if the set is subsetRecursion, false otherwise.
      */
     public boolean compare(LWWElementSet other) {
         return other.addSet.keySet().containsAll(addSet.keySet()) && other.removeSet.keySet().containsAll(removeSet.keySet());

src/main/java/com/thealgorithms/datastructures/crdt/ORSet.java

@@ -132,10 +132,10 @@ private String generateUniqueTag() {
     }
 
     /**
-     * Compares this Add-Wins OR-Set with another OR-Set to check if elements and tombstones are a subset.
+     * Compares this Add-Wins OR-Set with another OR-Set to check if elements and tombstones are a subsetRecursion.
      *
      * @param other the other OR-Set to compare
-     * @return true if the sets are subset, false otherwise
+     * @return true if the sets are subsetRecursion, false otherwise
      */
     public boolean compare(ORSet<T> other) {
         Set<Pair<T>> union = new HashSet<>(elements);

src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java

@@ -61,7 +61,7 @@ public void remove(T element) {
      * Compares the current 2P-Set with another 2P-Set.
      *
      * @param otherSet The other 2P-Set to compare with.
-     * @return True if both SetA and SetR are subset, otherwise false.
+     * @return True if both SetA and SetR are subsetRecursion, otherwise false.
      */
     public boolean compare(TwoPSet<T> otherSet) {
         return otherSet.setA.containsAll(setA) && otherSet.setR.containsAll(setR);

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

@@ -60,7 +60,7 @@ static class Graph {
     }
 
     /**
-     * Represents a subset for Union-Find operations
+     * Represents a subsetRecursion for Union-Find operations
      */
     private static class Component {
         int parent;
@@ -89,7 +89,7 @@ private static class BoruvkaState {
         /**
          * Adds the cheapest edges to the result list and performs Union operation on the subsets.
          *
-         * @param cheapest Array containing the cheapest edge for each subset.
+         * @param cheapest Array containing the cheapest edge for each subsetRecursion.
          */
         void merge(final Edge[] cheapest) {
             for (int i = 0; i < graph.vertex; ++i) {
@@ -115,9 +115,9 @@ boolean hasMoreEdgesToAdd() {
         }
 
         /**
-         * Computes the cheapest edges for each subset in the Union-Find structure.
+         * Computes the cheapest edges for each subsetRecursion in the Union-Find structure.
          *
-         * @return an array containing the cheapest edge for each subset.
+         * @return an array containing the cheapest edge for each subsetRecursion.
          */
         private Edge[] computeCheapestEdges() {
             Edge[] cheapest = new Edge[graph.vertex];
@@ -153,11 +153,11 @@ private static Component[] initializeComponents(final Graph graph) {
     }
 
     /**
-     * Finds the parent of the subset using path compression
+     * Finds the parent of the subsetRecursion using path compression
      *
      * @param components array of subsets
-     * @param i          index of the subset
-     * @return the parent of the subset
+     * @param i          index of the subsetRecursion
+     * @return the parent of the subsetRecursion
      */
     static int find(final Component[] components, final int i) {
         if (components[i].parent != i) {
@@ -170,8 +170,8 @@ static int find(final Component[] components, final int i) {
      * Performs the Union operation for Union-Find
      *
      * @param components array of subsets
-     * @param x          index of the first subset
-     * @param y          index of the second subset
+     * @param x          index of the first subsetRecursion
+     * @param y          index of the second subsetRecursion
      */
     static void union(Component[] components, final int x, final int y) {
         final int xroot = find(components, x);

src/main/java/com/thealgorithms/dynamicprogramming/MinimumSumPartition.java

@@ -3,8 +3,8 @@
 import java.util.Arrays;
 
 /*
-Given an array of non-negative integers , partition the array in two subset that
-difference in sum of elements for both subset minimum.
+Given an array of non-negative integers , partition the array in two subsetRecursion that
+difference in sum of elements for both subsetRecursion minimum.
 Return the minimum difference in sum of these subsets you can achieve.
 
 Input:  array[] = {1, 6, 11, 4}
@@ -35,7 +35,7 @@ public static int minimumSumPartition(final int[] array) {
         boolean[] dp = new boolean[sum / 2 + 1];
         dp[0] = true; // Base case , don't select any element from array
 
-        // Find the closest sum of subset array that we can achieve which is closest to half of sum of full array
+        // Find the closest sum of subsetRecursion array that we can achieve which is closest to half of sum of full array
         int closestPartitionSum = 0;
 
         for (int i = 0; i < array.length; i++) {

src/main/java/com/thealgorithms/dynamicprogramming/PartitionProblem.java

@@ -3,7 +3,7 @@
  *
  * Description: The partition problem is a classic problem in computer science
  * that asks whether a given set can be partitioned into two subsets such that
- * the sum of elements in each subset is the same.
+ * the sum of elements in each subsetRecursion is the same.
  *
  * Example:
  * Consider nums = {1, 2, 3}
@@ -24,17 +24,17 @@ private PartitionProblem() {
 
     /**
      * Test if a set of integers can be partitioned into two subsets such that the sum of elements
-     * in each subset is the same.
+     * in each subsetRecursion is the same.
      *
      * @param nums the array contains integers.
-     * @return {@code true} if two subset exists, otherwise {@code false}.
+     * @return {@code true} if two subsetRecursion exists, otherwise {@code false}.
      */
     public static boolean partition(int[] nums) {
         // calculate the sum of all the elements in the array
         int sum = Arrays.stream(nums).sum();
 
         // it will return true if the sum is even and the array can be divided into two
-        // subarrays/subset with equal sum. and here i reuse the SubsetSum class from dynamic
+        // subarrays/subsetRecursion with equal sum. and here i reuse the SubsetSum class from dynamic
         // programming section to check if there is exists a subsetsum into nums[] array same as the
         // given sum
         return (sum & 1) == 0 && SubsetSum.subsetSum(nums, sum / 2);

src/main/java/com/thealgorithms/dynamicprogramming/SubsetCount.java

@@ -15,12 +15,12 @@ private SubsetCount() {
      * Method to find out the number of subsets present in the given array with a sum equal to
      * target. Time Complexity is O(n*target) and Space Complexity is O(n*target)
      * @param arr is the input array on which subsets are  to searched
-     * @param target is the sum of each element of the subset taken together
+     * @param target is the sum of each element of the subsetRecursion taken together
      *
      */
     public static int getCount(int[] arr, int target) {
         /*
-         * Base Cases - If target becomes zero, we have reached the required sum for the subset
+         * Base Cases - If target becomes zero, we have reached the required sum for the subsetRecursion
          * If we reach the end of the array arr then, either if target==arr[end], then we add one to
          * the final count Otherwise we add 0 to the final count
          */
@@ -50,7 +50,7 @@ public static int getCount(int[] arr, int target) {
      * same problem This approach is a bit better in terms of Space Used Time Complexity is
      * O(n*target) and Space Complexity is O(target)
      * @param arr is the input array on which subsets are  to searched
-     * @param target is the sum of each element of the subset taken together
+     * @param target is the sum of each element of the subsetRecursion taken together
      */
     public static int getCountSO(int[] arr, int target) {
         int n = arr.length;

src/main/java/com/thealgorithms/dynamicprogramming/SubsetSum.java

@@ -5,22 +5,22 @@ private SubsetSum() {
     }
 
     /**
-     * Test if a set of integers contains a subset that sums to a given integer.
+     * Test if a set of integers contains a subsetRecursion that sums to a given integer.
      *
      * @param arr the array containing integers.
-     * @param sum the target sum of the subset.
-     * @return {@code true} if a subset exists that sums to the given value, otherwise {@code false}.
+     * @param sum the target sum of the subsetRecursion.
+     * @return {@code true} if a subsetRecursion exists that sums to the given value, otherwise {@code false}.
      */
     public static boolean subsetSum(int[] arr, int sum) {
         int n = arr.length;
         boolean[][] isSum = new boolean[n + 1][sum + 1];
 
-        // Initialize the first column to true since a sum of 0 can always be achieved with an empty subset.
+        // Initialize the first column to true since a sum of 0 can always be achieved with an empty subsetRecursion.
         for (int i = 0; i <= n; i++) {
             isSum[i][0] = true;
         }
 
-        // Fill the subset sum matrix
+        // Fill the subsetRecursion sum matrix
         for (int i = 1; i <= n; i++) {
             for (int j = 1; j <= sum; j++) {
                 if (arr[i - 1] <= j) {

src/test/java/com/thealgorithms/Recursion/GenerateUniqueSubsetsTest.java

@@ -0,0 +1,36 @@
+package com.thealgorithms.Recursion;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public final class GenerateUniqueSubsetsTest {
+
+    @Test
+    void subsetRecursionTestOne() {
+        String str = "aba";
+        String[] expected = new String[] {"", "a", "aa", "ab", "aba", "b", "ba"};
+
+        List<String> ans = GenerateUniqueSubsets.subsetRecursion(str);
+        assertArrayEquals(ans.toArray(), expected);
+    }
+
+    @Test
+    void subsetRecursionTestTwo() {
+        String str = "abba";
+        String[] expected = new String[] {"", "a", "aa", "ab", "aba", "abb", "abba", "b", "ba", "bb", "bba"};
+
+        List<String> ans = GenerateUniqueSubsets.subsetRecursion(str);
+        assertArrayEquals(ans.toArray(), expected);
+    }
+
+    @Test
+    void subsetRecursionTestThree() {
+        String str = "aaa";
+        String[] expected = new String[] {"", "a", "aa", "aaa"};
+
+        List<String> ans = GenerateUniqueSubsets.subsetRecursion(str);
+        assertArrayEquals(ans.toArray(), expected);
+    }
+}