leetcode 48. 旋转图像 Rotate Image（使用c++/java/python）

先上下翻转，再按主对角线对称。

执行用时： c++ 16ms； java 1ms； python 44ms

c++

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

java

class Solution {
    public void rotate(int[][] matrix) {
        int len = matrix.length;
        for(int i = 0; i < len / 2; i++) 
        {
            int[] tmp = matrix[i];
            matrix[i] = matrix[len - 1 - i];
            matrix[len - 1 - i] = tmp;
        }
        
        for(int i = 0; i < len; i++) 
        {
            for(int j = 0; j < i; j++) 
            {
                int tmp = matrix[i][j];
                matrix[i][j] = matrix[j][i];
                matrix[j][i] = tmp;
            }
        }
    }
}

python

class Solution:
    def rotate(self, matrix):
        """
        :type matrix: List[List[int]]
        :rtype: void Do not return anything, modify matrix in-place instead.
        """
        matrix.reverse()
        for i in range(len(matrix)):
            for j in range(i):
                matrix[i][j], matrix[j][i] = matrix[j][i], matrix[i][j]