Rotate Image

先按照对角线翻转，再按照x轴翻转
 1 public class Solution {
 2     public void rotate(int[][] matrix) {
 3         // IMPORTANT: Please reset any member data you declared, as
 4         // the same Solution instance will be reused for each test case.
 5         int len = matrix.length;
 6         if(len == 0)
 7             return;
 8         
 9         for(int i = 0; i < len - 1; i++){
10             for(int j = 0; j < len -i; j++){
11                 swap(matrix, i, j, len - 1 - j, len - 1 -i);
12             }
13         }
14         
15         
16         for(int i = 0; i < len / 2; i++){
17             for(int j = 0; j < len; j++){
18                 swap(matrix, i, j, len - 1 -i, j);
19             }
20         }
21     }
22     
23     public void swap(int[][] matrix, int i, int j, int m, int n){
24         int tmp = matrix[i][j];
25         matrix[i][j] = matrix[m][n];
26         matrix[m][n] = tmp;
27     }
28 }