Rotate Image

Source

• leetcode: 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?

Java

public class Solution {
    public void rotate(int[][] matrix) {
        int n = matrix.length;

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