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?

//原地旋转90度。
//1.沿主对角线所有元素交换
//2.沿着垂直中轴线方向所有元素交换

class Solution {
public:
    void rotate(vector<vector<int>>& matrix) {
        for(int i = 0; i < matrix.size(); i++)
            for(int j = 0; j <= i; j++)
                swap(matrix[i][j], matrix[j][i]);
                
        for(int i = 0, j = matrix.size() - 1; i < j; i++, j--)
            for(int k = 0; k < matrix.size(); k++)
                swap(matrix[k][i], matrix[k][j]);
    }
};

//原地旋转90度。

//1.沿主对角线所有元素交换

//2.沿着垂直中轴线方向所有元素交换

class Solution {

public:

void rotate(vector<vector<int>>& matrix) {

for(int i = 0; i < matrix.size(); i++)

for(int j = 0; j <= i; j++)

swap(matrix[i][j], matrix[j][i]);

for(int i = 0, j = matrix.size() - 1; i < j; i++, j--)

for(int k = 0; k < matrix.size(); k++)

swap(matrix[k][i], matrix[k][j]);

}

};