Python如何判断数独是否合法

class Solution:

# @param board, a 9x9 2D array
# @return a boolean
def isValidSudoku(self, board):
 rows = [list(lst[::]) for lst in board]
 columns = [[lst[idx] for lst in board] for idx in range(9)]
 blocks_origin = [board[row][column] for x in [[0, 1, 2], [3, 4, 5], [6, 7, 8]] for y in [[0, 1, 2], [3, 4, 5], [6, 7, 8]] for row in x for column in y] # 利用一些技巧直接按块储存数据
 blocks = [[blocks_origin[row * 9 + column] for column in range(9)] for row in range(9)]
 check = lambda lst: all([lst.count(x) == 1 for x in lst if x != '.']) # 判断一条记录（按某种方式排列的九个数字）是否合法
 return all([check(x) for style in (rows, columns, blocks) for x in style]) # 一步搞定