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?

public class Solution {
	    public void rotate(int[][] matrix) {
	        if(matrix == null) return ;
	        int rows = matrix.length;
	        if(rows <= 1) return;
	        
	        for(int left=0, right=rows-1; left<right; left++, right--){
	        	for(int high=left, low=right; high<low; high++, low--){
	        		int t = matrix[high][left];
	        		matrix[high][left] = matrix[low][left];
	        		matrix[low][left] = matrix[low][right];
	        		matrix[low][right] = matrix[high][right];
	        		matrix[high][right] = t;
	        	}
	        }
	    }
	}