Merge pull request #582 from priyashuu/rotate

Add RotateImage algorithm implementation in Java

Author: Pradeepsingh61

Java/algorithms/arrays/RotateImage.java

@@ -0,0 +1,56 @@
+/*
+ * Algorithm Name:Rotate Image .
+ * Programming Language: Java
+ * Category: Array ,matrix
+ * Difficulty Level: Medium
+ *
+ * Author: Priya Rani 
+ *
+ * Algorithm Description: You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise).
+
+  You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the rotation.
+
+ 
+* Time Complexity:	O(n²)	Each element is visited once during transpose and once during row reversal
+* Space Complexity: O(1)	Rotation is done in-place without using extra data structures
+*/
+import java.util.*;
+
+public class RotateImage {
+    public void rotate(int[][] matrix) {
+        int n = matrix.length;
+
+        for (int i = 0; i < n; i++) {
+            for (int j = i + 1; j < n; j++) {
+                int temp = matrix[i][j];
+                matrix[i][j] = matrix[j][i];
+                matrix[j][i] = temp;
+            }
+        }
+
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < n / 2; j++) {
+                int temp = matrix[i][j];
+                matrix[i][j] = matrix[i][n - 1 - j];
+                matrix[i][n - 1 - j] = temp;
+            }
+        }
+    }
+
+    public static void main(String[] args) {
+        RotateImage solution = new RotateImage();
+
+        int[][] matrix = {
+            {1, 2, 3},
+            {4, 5, 6},
+            {7, 8, 9}
+        };
+
+        solution.rotate(matrix);
+
+
+        for (int[] row : matrix) {
+            System.out.println(Arrays.toString(row));
+        }
+    }
+}