Rotate Imag

You are given an n x n 2D matrix representing an image.
Rotate the image by 90 degrees (clockwise).
Follow up:
Could you do this in-place?

Naive Way: To do it in-place, need to start from a point, find its corresponding new position, and then start with the new position, find its corresponding position...

The range of two index pointers is important.

 public class Solution {  
   public void rotate(int[][] matrix) {  
     int n = matrix.length;  
     for(int i = 0;i < n-1;i++){  
       for(int j = i;j < n-1-i;j++){  
         int count = 0;  
         int x = i,y = j;  
         int pre = matrix[x][y];  
         while(count++ < 4){  
           int temp = matrix[y][n-1-x];  
           matrix[y][n-1-x] = pre;  
           int temp_x = x;  
           x = y;  
           y = n-1-temp_x;  
           pre = temp;  
         }  
       }  
     }  
     return;  
   }  
 }