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。
用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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