36. Valid Sudoku python

Determine if a 9x9 Sudoku board is valid. Only the filled cells need to be validated according to the following rules:

1. Each row must contain the digits 1-9 without repetition.
2. Each column must contain the digits 1-9 without repetition.
3. Each of the 9 3x3 sub-boxes of the grid must contain the digits 1-9 without repetition.

A partially filled sudoku which is valid.

The Sudoku board could be partially filled, where empty cells are filled with the character '.'.

Example 1:

Input:
[
  ["5","3",".",".","7",".",".",".","."],
  ["6",".",".","1","9","5",".",".","."],
  [".","9","8",".",".",".",".","6","."],
  ["8",".",".",".","6",".",".",".","3"],
  ["4",".",".","8",".","3",".",".","1"],
  ["7",".",".",".","2",".",".",".","6"],
  [".","6",".",".",".",".","2","8","."],
  [".",".",".","4","1","9",".",".","5"],
  [".",".",".",".","8",".",".","7","9"]
]
Output: true

Example 2:

Input:
[
  ["8","3",".",".","7",".",".",".","."],
  ["6",".",".","1","9","5",".",".","."],
  [".","9","8",".",".",".",".","6","."],
  ["8",".",".",".","6",".",".",".","3"],
  ["4",".",".","8",".","3",".",".","1"],
  ["7",".",".",".","2",".",".",".","6"],
  [".","6",".",".",".",".","2","8","."],
  [".",".",".","4","1","9",".",".","5"],
  [".",".",".",".","8",".",".","7","9"]
]
Output: false
Explanation: Same as Example 1, except with the 5 in the top left corner being 
    modified to 8. Since there are two 8's in the top left 3x3 sub-box, it is invalid.

Note:

• A Sudoku board (partially filled) could be valid but is not necessarily solvable.
• Only the filled cells need to be validated according to the mentioned rules.
• The given board contain only digits 1-9 and the character '.'.
• The given board size is always 9x9.

题意：判断同一行，同一列或者同一个3*3里面的数据，是否都是在 0~9之间，而且没有重复

思路：最简单的思路是按照传统思路每个进行判断，但是耗时太多，每个数据需要进行三次判断。我们可以进行一次判断，即可得到最终的结果。但是需要存三个二维数组row,column,another（初始化为false），每个数组分别存行，列，或者3*3里的数据。row里面存行数，和里面的num，碰到的时候变为True。行为i ,num为j,即表示同一个行的数据0~9只能出现一次。another存的是每个3*3，用k=i/3*3+j/3，来表示是第几个3*3.

class Solution(object):
    def isValidSudoku(self, board):
        """
        :type board: List[List[str]]
        :rtype: bool
        """
        row=[[False for i in range(9)] for j in range(9)]
        column=[[False for i in range(9)] for j in range(9)]
        another=[[False for i in range(9)] for j in range(9)]
        for i in range(9):
            for j in range(9):
                k=i/3*3+j/3
                if(board[i][j]=='.'):
                    continue
                num=int(board[i][j])-1
                if(row[i][num] or column[j][num] or another[k][num]):
                    return False
                row[i][num]=column[j][num]=another[k][num]=True
        return True