in Array ~ read.

Rotate Image

48. Rotate Image

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 n = matrix.length;

        for (int i = 0; i < n/2; i++) {
            for (int j = i; j < n-1-i; j++) {
                int temp = matrix[i][j];
                matrix[i][j] = matrix[n-1-j][i];
                matrix[n-1-j][i] = matrix[n-1-i][n-1-j];
                matrix[n-1-i][n-1-j] = matrix[j][n-1-i];
                matrix[j][n-1-i] = temp;
            }
        }
    }
}

Hope this helps,
Michael