Given a matrix A, return the transpose of A.
The transpose of a matrix is the matrix flipped over it‘s main diagonal, switching the row and column indices of the matrix.
求矩阵的转置
踩了一个python的坑 x = [[0] * n] * m 内层的字数组是同一个，改变[0][1]的同时[1][1] [2][1] ...[m][1]都被改了。因此不能这么初始化二维list。
class Solution(object): def transpose(self, A): """ :type A: List[List[int]] :rtype: List[List[int]] """ n = len(A) m = len(A[0]) B = [] for i in range(m): B.append([0] * n) for i in range(m): for j in range(n): B[i][j] = A[j][i] return B
原文：https://www.cnblogs.com/whatyouthink/p/13218274.html