Leetcode_Python 48 旋转图像

class Solution(object):
    def rotate(self, matrix):
        """
        :type matrix: List[List[int]]
        :rtype: None Do not return anything, modify matrix in-place instead.
        """
        N = len(matrix)     #列数==列数
        for i in range(N):
            for j in range(N//2):
                a = matrix[i][N-1-j]
                matrix[i][N-1-j] = matrix[i][j]
                matrix[i][j] = a
        for i in range(N):
            for j in range(N-i-1):
                a = matrix[N-j-1][N-i-1]
                matrix[N-j-1][N-i-1] = matrix[i][j]
                matrix[i][j] = a
        return matrix