Created Remove Duplicate From Sorted Array

Implement in-place duplicate removal from sorted array using two-pointer technique.

Author: amankumar100

src/main/java/com/thealgorithms/others/RemoveDuplicatesFromSortedArray.java

@@ -0,0 +1,75 @@
+package com.thealgorithms.others;
+
+import java.util.Scanner;
+
+/**
+ * Remove duplicates from sorted array.
+ *
+ * <p>
+ * Given an integer array nums sorted in non-decreasing order, remove the
+ * duplicates in-place such that each unique element appears only once.
+ * The relative order of the elements should be kept the same. Then return
+ * the number of unique elements in nums.
+ *
+ * <p>
+ */
+public final class RemoveDuplicatesFromSortedArray {
+
+    private RemoveDuplicatesFromSortedArray() {
+        // private constructor to prevent instantiation
+    }
+
+    /**
+     * Main method with user input.
+     */
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+
+        System.out.println("Enter size of sorted array:");
+        int n = scanner.nextInt();
+
+        if (n <= 0) {
+            System.out.println("Invalid array size.");
+            scanner.close();
+            return;
+        }
+
+        int[] nums = new int[n];
+        System.out.println("Enter " + n + " integers in non-decreasing order:");
+        for (int i = 0; i < n; i++) {
+            nums[i] = scanner.nextInt();
+        }
+
+        int k = removeDuplicates(nums);
+
+        System.out.println("Number of unique elements: " + k);
+        System.out.print("Array after removing duplicates: ");
+        for (int i = 0; i < k; i++) {
+            System.out.print(nums[i] + " ");
+        }
+        System.out.println();
+
+        scanner.close();
+    }
+
+    /**
+     * Removes duplicates from a sorted array in-place using O(1) space.
+     *
+     * @param nums The input sorted array
+     * @return The number of unique elements
+     */
+    public static int removeDuplicates(int[] nums) {
+        if (nums == null || nums.length == 0) {
+            return 0;
+        }
+
+        int j = 0; // points to last unique element
+        for (int i = 1; i < nums.length; i++) {
+            if (nums[j] != nums[i]) {
+                j++;
+                nums[j] = nums[i];
+            }
+        }
+        return j + 1;
+    }
+}