36. 有效的数独

逃离我推掉我的手 2022-09-07 01:31 286阅读 0赞

[https://leetcode-cn.com/problems/valid-sudoku/][https_leetcode-cn.com_problems_valid-sudoku]

难度中等571

请你判断一个 `9x9` 的数独是否有效。只需要** 根据以下规则** ，验证已经填入的数字是否有效即可。

1.  数字 `1-9` 在每一行只能出现一次。
2.  数字 `1-9` 在每一列只能出现一次。
3.  数字 `1-9` 在每一个以粗实线分隔的 `3x3` 宫内只能出现一次。（请参考示例图）

数独部分空格内已填入了数字，空白格用 `'.'` 表示。

**注意：**

*  一个有效的数独（部分已被填充）不一定是可解的。
 *  只需要根据以上规则，验证已经填入的数字是否有效即可。

**示例 1：**

![1377561680611c155bece0f170ae6b30.png][]

输入：board = 
    [["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"]]
    输出：true

**示例 2：**

输入：board = 
    [["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"]]
    输出：false
    解释：除了第一行的第一个数字从 5 改为 8 以外，空格内其他数字均与 示例1 相同。 但由于位于左上角的 3x3 宫内有两个 8 存在, 因此这个数独是无效的。

**提示：**

*  `board.length == 9`
 *  `board[i].length == 9`
 *  `board[i][j]` 是一位数字或者 `'.'`

通过次数166,506提交次数265,025

class Solution {
        public boolean isValidSudoku(char[][] board) {
            //横9
            for(int i=0;i<9;i++)
            {
                int [] ans = new int [10];
                for(int j=0;j<9;j++)
                {
                    if(board[i][j]!='.')
                    {
                        
                        if(++ans[board[i][j]-'0'] >1) return false;
                    } 
                }
            }
    
             //竖9
            for(int i=0;i<9;i++)
            {
                int [] ans = new int [10];
                for(int j=0;j<9;j++)
                {
                    if(board[j][i]!='.' )
                    {
                      if(++ans[board[j][i]-'0']>1) return false;
                    } 
                    
                }
                System.out.println();
            }
    
            //3*3
            int i=0;
            int j=0;
             for(int x=0;x<9;x++)
             {
                 int [] ans = new int [10];
                 for(int p = 0;p<3;p++)
                 {
                     for(int q=0;q<3;q++)
                     {
                         if(board[p+i][q+j]!='.' && ++ans[board[p+i][q+j]-'0'] > 1) return false;
                     }
                 }
                 j+=3;
                 if(j==9)
                 {
                     i+=3;
                     j=0;
                 }
             }
            return true;
        }
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0dldHVnbHk_size_16_color_FFFFFF_t_70][]

[https_leetcode-cn.com_problems_valid-sudoku]: https://leetcode-cn.com/problems/valid-sudoku/
[1377561680611c155bece0f170ae6b30.png]: /images/20220829/3febd7507d634b4595c8e629262bcca0.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0dldHVnbHk_size_16_color_FFFFFF_t_70]: /images/20220829/f73b95bbef0f4857a82239a90a63c1d5.png