判斷一個9x9 的數獨是否有效。只需要根據以下規則，驗證已經填入的數字是否有效即可。

數字1-9在每一行只能出現一次。
數字1-9在每一列只能出現一次。
數字1-9在每一個以粗實線分隔的3x3宮內只能出現一次。


上圖是一個部分填充的有效的數獨。

數獨部分空格內已填入了數字，空白格用'.'表示。

示例1:

輸入:
[
  ["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"]
]
輸出: true
示例2:

輸入:
[
 ["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"]
]
輸出: false
解釋: 除了第一行的第一個數字從 5 改為 8 以外，空格內其他數字均與 示例1 相同。
     但由於位於左上角的 3x3 宮內有兩個 8 存在, 因此這個數獨是無效的。
說明:

一個有效的數獨（部分已被填充）不一定是可解的。
只需要根據以上規則，驗證已經填入的數字是否有效即可。
給定數獨序列只包含數字1-9和字元'.'。
給定數獨永遠是9x9形式的。

來源：力扣（LeetCode）
連結：https://leetcode-cn.com/problems/valid-sudoku
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from typing import List
class Solution:
    def isValidSudoku(self, board: List[List[str]]) -> bool:
        def isvalid(ls:List)->bool:
            d=dict()
            for x in ls:
                if x!='.' and x in d:
                    return False
                if x!='.' and x not in d:
                    d[x]=1
            return True

        #行
        for x in board:
            if not isvalid(x):
                return False
        
        #列

        for i in range(9):
            ls=[]
            for j in range(9):
                ls.append(board[j][i])
            if not isvalid(ls):
                return False
        
        for i in range(0,9,3):
            for j in range(0,9,3):
                ls=[]
                for k in range(0,3):
                    for l in range(0,3):
                        ls.append(board[i+k][j+l])
                if not isvalid(ls):
                    return False
        return True