LeetCode 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?

水题

class Solution {
public:
    void rotate(vector<vector<int>>& matrix) {

        int n = matrix.size();

        for(int i=0; i<n/2; ++ i)
        {
            for(int j=i, s=0; s < n-i*2-1; ++ s, ++ j)
            {
                int t = 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] = t;
            }
        }
    }
};