You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise).
You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the rotation.
public void rotate(int[][] matrix) {
int s = 0, e = matrix.length - 1;
while(s < e){
int[] temp = matrix[s];
matrix[s] = matrix[e];
matrix[e] = temp;
s++; e--;
}
for(int i = 0; i < matrix.length; i++){
for(int j = i+1; j < matrix[i].length; j++){
int temp = matrix[i][j];
matrix[i][j] = matrix[j][i];
matrix[j][i] = temp;
}
}
}
