1 public class Solution {
 2     public void rotate(int[][] matrix) {
 3         int length = matrix.length;
 4         for (int i = 0; i < (length + 1) / 2; i++) {
 5             for (int j = i; j < length - 1 - i; j++) {
 6                 int tmp = matrix[i][j];
 7                 matrix[i][j] = matrix[length - 1 - j][i];
 8                 matrix[length - 1 - j][i] = matrix[length - 1 - i][length - 1 - j];
 9                 matrix[length - 1 - i][length - 1 - j] = matrix[j][length - 1 - i];
10                 matrix[j][length - 1 - i] = tmp;
11             }
12         }
13         return;
14     }
15 }

 1 /*
 2  * clockwise rotate
 3  * first reverse up to down, then swap the symmetry
 4  * 1 2 3     7 8 9     7 4 1
 5  * 4 5 6  => 4 5 6  => 8 5 2
 6  * 7 8 9     1 2 3     9 6 3
 7 */
 8 void rotate(vector<vector<int> > &matrix) {
 9     reverse(matrix.begin(), matrix.end());
10     for (int i = 0; i < matrix.size(); ++i) {
11         for (int j = i + 1; j < matrix[i].size(); ++j)
12             swap(matrix[i][j], matrix[j][i]);
13     }
14 }

 1 public class Solution {
 2     public void rotate(int[][] matrix) {
 3         for(int i = 0; i<matrix.length; i++){
 4             for(int j = i; j<matrix[0].length; j++){
 5                 int temp = 0;
 6                 temp = matrix[i][j];
 7                 matrix[i][j] = matrix[j][i];
 8                 matrix[j][i] = temp;
 9             }
10         }
11         for(int i =0 ; i<matrix.length; i++){
12             for(int j = 0; j<matrix.length/2; j++){
13                 int temp = 0;
14                 temp = matrix[i][j];
15                 matrix[i][j] = matrix[i][matrix.length-1-j];
16                 matrix[i][matrix.length-1-j] = temp;
17             }
18         }
19     }
20 }

class Solution:def rotate(self, A):A[:] = zip(*A[::-1])

class Solution:def rotate(self, A):A[:] = map(list, zip(*A[::-1]))