48. Rotate Image

 1     public void rotate(int[][] matrix) {
 2         if(matrix == null || matrix.length == 0) { 
 3             return;
 4         }
 5         int n = matrix.length;
 6         int[][] res = new int[n][n];
 7         for(int i = 0; i < n; i++) {
 8             for(int j = 0; j < n; j++) {
 9                 res[j][n - 1 - i] = matrix[i][j];
10             }
11         }
12         for(int i = 0; i < n; i++) {
13             for(int j = 0; j <n; j++) {
14                 matrix[i][j] = res[i][j];
15             }
16         }
17     }