LeetCode數獨問題中Bitset的巧妙用處

2022-05-22 17:57:12 字數 1890 閱讀 7323

判斷乙個 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在每乙個以粗實線分隔的3x3宮內只能出現一次。

上圖是乙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: 除了第一行的第乙個數字從 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。

bitset​代表每一行每一列中對應的數字是否出現過

class solution 

}return true;}};

難度困難579

編寫乙個程式,通過已填充的空格來解決數獨問題。

乙個數獨的解法需遵循如下規則

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在每乙個以粗實線分隔的3x3宮內只能出現一次。

空白格用'.'表示。

乙個數獨。

答案被標成紅色。

class solution 

vectorgetnext(vector> &board)

}helper(board, cnt);}};

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