36. Valid Sudoku

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本文介绍了一种使用Python实现的高效算法，用于判断一个部分填充的数独是否符合数独的基本规则。通过利用集合和哈希表，该算法能够快速检查每一行、每一列以及每一个宫内的数字是否重复。

36. Valid Sudoku

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Discription:

Determine if a Sudoku is valid, according to: Sudoku Puzzles - The Rules.

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

A partially filled sudoku which is valid.

Note:
A valid Sudoku board (partially filled) is not necessarily solvable. Only the filled cells need to be validated.

Analyze:

Code 1:

class Solution(object):
    def isValidSudoku(self, board):
        """
        :type board: List[List[str]]
        :rtype: bool
        """
        return 1 == max(collections.Counter(
            x
            for i, row in enumerate(board)  
            for j, c in enumerate(row)
            if c != '.'
            for x in ((c, i), (j, c), (i/3, j/3, c))
        ).values() + [1])