36. Valid Sudoku leetcode Python new season 2016

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.

class Solution(object):
    def valid(self, x, y, tmp, board):
        for i in range(9):
            if board[i][y] == tmp:
                return False
        for j in range(9):
            if board[x][j] == tmp:
                return False
        for i in range(3):
            for j in range(3):
                if board[(x / 3) * 3 + i][( y / 3) * 3 + j] == tmp:
                    return False
        return True
    def isValidSudoku(self, board):
        """
        :type board: List[List[str]]
        :rtype: bool
        """
        for i in range(9):
            for j in range(9):
                if board[i][j] == '.':
                    continue
                tmp = board[i][j]
                board[i][j] = 'D'
                if self.valid(i, j, tmp, board) == False:
                    return False
                board[i][j] = tmp
        return True