matrix rotation : done

Author: Ram swaroop

src/me/ramswaroop/arrays/RotateMatrixBy90Degrees.java

@@ -0,0 +1,47 @@
+package me.ramswaroop.arrays;
+
+/**
+ * Created by IntelliJ IDEA.
+ *
+ * @author: ramswaroop
+ * @date: 8/22/15
+ * @time: 4:03 PM
+ */
+public class RotateMatrixBy90Degrees {
+
+    public static int[][] rotateMatrixBy90DegreesRight(int[][] a) {
+        int rows = a.length, columns = a[0].length;
+        int[][] rotatedMatrix = new int[columns][rows];
+
+        for (int i = 0; --rows >= 0 && i < a.length; i++) {
+            for (int j = 0; j < a[0].length; j++) {
+                rotatedMatrix[j][rows] = a[i][j];
+            }
+        }
+
+        return rotatedMatrix;
+    }
+
+    private static void print2DMatrix(int[][] a) {
+        for (int i = 0; i < a.length; i++) {
+            for (int j = 0; j < a[0].length; j++) {
+                System.out.print(a[i][j]);
+            }
+            System.out.println();
+        }
+    }
+
+    public static void main(String a[]) {
+        int[][] ar = new int[][]{{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
+        print2DMatrix(ar);
+        System.out.println("--------");
+        print2DMatrix(rotateMatrixBy90DegreesRight(ar));
+        
+        System.out.println("========");
+        
+        ar = new int[][]{{1, 2, 3}, {4, 5, 6}, {7, 8, 9}, {0, 5, 7}};
+        print2DMatrix(ar);
+        System.out.println("--------");
+        print2DMatrix(rotateMatrixBy90DegreesRight(ar));
+    }
+}