week 2 48. Rotate Image

public class Solution {
    public void rotate(int[][] matrix) {
        if(matrix == null || matrix.length == 0 || matrix[0].length == 0){
            return;
        }
        
        int row = matrix.length;
        int col = matrix[0].length;
        
        for (int i = 0; i < row; i++){
            for (int j = 0; j < i; j++){
                swap (matrix, i, j, j, i);
            }
        }
        
        for (int i = 0; i < row; i++){
            for (int j = 0; j < col / 2; j++){
                swap (matrix, i, j, i, col-j-1);
            }
        }
    }
    
    public void swap (int [][] matrix, int i, int j, int x, int y){
        int temp = matrix [i][j];
        matrix [i][j] = matrix [x][y];
        matrix [x][y] = temp;
    }
}