diff --git a/DIRECTORY.md b/DIRECTORY.md
index b621216da7f1..2ec4aac6a6da 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -27,7 +27,6 @@
             * [NonRepeatingNumberFinder](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinder.java)
             * [NumbersDifferentSigns](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/NumbersDifferentSigns.java)
             * [ReverseBits](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/ReverseBits.java)
-            * [SetKthBit](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SetKthBit.java)
             * [SingleBitOperations](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/bitmanipulation/SingleBitOperations.java)
           * ciphers
             * a5
@@ -271,6 +270,7 @@
             * [AmicableNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/AmicableNumber.java)
             * [Area](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Area.java)
             * [Armstrong](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Armstrong.java)
+            * [AutoCorrelation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/AutoCorrelation.java)
             * [AutomorphicNumber](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/AutomorphicNumber.java)
             * [Average](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Average.java)
             * [BinaryPow](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/BinaryPow.java)
@@ -281,6 +281,7 @@
             * [Combinations](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Combinations.java)
             * [Convolution](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/Convolution.java)
             * [ConvolutionFFT](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/ConvolutionFFT.java)
+            * [CrossCorrelation](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/CrossCorrelation.java)
             * [DeterminantOfMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/DeterminantOfMatrix.java)
             * [DigitalRoot](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/DigitalRoot.java)
             * [DistanceFormula](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/DistanceFormula.java)
@@ -587,7 +588,6 @@
             * [NonRepeatingNumberFinderTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NonRepeatingNumberFinderTest.java)
             * [NumbersDifferentSignsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/NumbersDifferentSignsTest.java)
             * [ReverseBitsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/ReverseBitsTest.java)
-            * [SetKthBitTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SetKthBitTest.java)
             * [SingleBitOperationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/bitmanipulation/SingleBitOperationsTest.java)
           * ciphers
             * a5
@@ -712,6 +712,7 @@
             * [AmicableNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AmicableNumberTest.java)
             * [AreaTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AreaTest.java)
             * [ArmstrongTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/ArmstrongTest.java)
+            * [AutoCorrelationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AutoCorrelationTest.java)
             * [AutomorphicNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AutomorphicNumberTest.java)
             * [AverageTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/AverageTest.java)
             * [BinaryPowTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/BinaryPowTest.java)
@@ -719,6 +720,7 @@
             * [CeilTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CeilTest.java)
             * [CollatzConjectureTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CollatzConjectureTest.java)
             * [CombinationsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CombinationsTest.java)
+            * [CrossCorrelationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/CrossCorrelationTest.java)
             * [DigitalRootTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DigitalRootTest.java)
             * [DistanceFormulaTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DistanceFormulaTest.java)
             * [DudeneyNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/maths/DudeneyNumberTest.java)
diff --git a/src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java b/src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java
index c0ce17b2802b..83dd3b72f2c8 100644
--- a/src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java
+++ b/src/main/java/com/thealgorithms/datastructures/crdt/TwoPSet.java
@@ -1,5 +1,4 @@
-package com.thealgorithms.datastructures.crdt;
-
+import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;
 
@@ -12,19 +11,35 @@
  * comparing with other 2P-Sets, and merging two 2P-Sets while preserving the remove-wins semantics.
  * (https://en.wikipedia.org/wiki/Conflict-free_replicated_data_type)
  *
+ * Changes made by @555vedant:
+ * - Made the constructor private and added a static factory method 'empty'.
+ * - Used 'Collections.unmodifiableSet' to create unmodifiable sets for 'setA' and 'setR' in the 'merge' method.
+ * - Updated the 'merge' method accordingly.
+ *
  * @author itakurah (Niklas Hoefflin) (https://github.com/itakurah)
+ * @author 555vedant (Your Name) (Your GitHub Profile)
  */
-
 public class TwoPSet<T> {
     private final Set<T> setA;
     private final Set<T> setR;
 
     /**
      * Constructs an empty Two-Phase Set.
+     * Note: This constructor is made private. Use the static factory method 'empty()' to create an empty set.
      */
-    public TwoPSet() {
-        this.setA = new HashSet<>();
-        this.setR = new HashSet<>();
+    private TwoPSet(Set<T> setA, Set<T> setR) {
+        this.setA = setA;
+        this.setR = setR;
+    }
+
+    /**
+     * Creates an empty Two-Phase Set.
+     *
+     * @param <T> the type of elements in the set.
+     * @return an empty Two-Phase Set.
+     */
+    public static <T> TwoPSet<T> empty() {
+        return new TwoPSet<>(new HashSet<>(), new HashSet<>());
     }
 
     /**
@@ -74,11 +89,15 @@ public boolean compare(TwoPSet<T> otherSet) {
      * @return A new 2P-Set containing the merged elements.
      */
     public TwoPSet<T> merge(TwoPSet<T> otherSet) {
-        TwoPSet<T> mergedSet = new TwoPSet<>();
-        mergedSet.setA.addAll(this.setA);
-        mergedSet.setA.addAll(otherSet.setA);
-        mergedSet.setR.addAll(this.setR);
-        mergedSet.setR.addAll(otherSet.setR);
-        return mergedSet;
+        Set<T> mergedSetA = new HashSet<>(setA);
+        mergedSetA.addAll(otherSet.setA);
+
+        Set<T> mergedSetR = new HashSet<>(setR);
+        mergedSetR.addAll(otherSet.setR);
+
+        return new TwoPSet<>(Collections.unmodifiableSet(mergedSetA), Collections.unmodifiableSet(mergedSetR));
     }
 }
+
+
+