link: https://leetcode.com/problems/rotate-image/
class Solution {
public void rotate(int[][] matrix) {
int n=matrix.length;
for(int layer=0; layer top
matrix[layer][i] = matrix[last-offset][first];
//bottom -> left
matrix[last-offset][first] = matrix[last][last-offset];
//right -> bottom
matrix[last][last-offset] = matrix[i][last];
//top -> right
matrix[i][last] = top;
}
}
}
}