Leetcode 36. 有效的数独(可以，一次过)

村上春种树 lv.2

发布时间：2022-09-21 15:57:33 242

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Leetcode 36. 有效的数独(可以，一次过)_实线

请你判断一个 9 x 9 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。

数字 1-9 在每一行只能出现一次。
数字 1-9 在每一列只能出现一次。
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）

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。
空白格用 '.' 表示。

示例 1：

Leetcode 36. 有效的数独(可以，一次过)_i++_02

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（1-9）或者 '.'

主要思路：map
Code:

class Solution {
public:
    bool isValidSudoku(vector<vector<char>>& board) {
        map<char,int>mymap;
        pair<map<char, int>::iterator, bool> ret;
        for(int j=0;j<board[0].size();j++)
        {
            for(int i=0;i<board.size();i++)
            {
                vector<char>sub=board[i];
                if(board[i][j]=='.')
                    continue;
                ret=mymap.insert(pair<char,int>(board[i][j],0));
                if(!ret.second)
                    return false;
                cout<<board[i][j]<<endl;
            }
            mymap.clear();
        }
        mymap.clear();
        for(int i=0;i<board.size();i++)
        {
            vector<char>sub=board[i];
            for(int j=0;j<sub.size();j++)
            {
                if(sub[j]=='.')
                    continue;
                ret=mymap.insert(pair<char,int>(sub[j],0));
                if(!ret.second)
                    return false;
            }
            mymap.clear();
        }
        mymap.clear();
        cout<<"++++"<<endl;
        int row=0;
        int col=0;
        do
        {
            
            for(int i=row;i<row+3;i++)
            {
                vector<char>sub=board[i];
                for(int j=col;j<col+3;j++)
                {
                    if(sub[j]=='.')
                        continue;
                    ret=mymap.insert(pair<char,int>(sub[j],0));
                    if(!ret.second)
                        return false;
                }
            }
            col+=3;
            mymap.clear();
            if(col==9)
            {
                col=0;
                row+=3;
                cout<<"row="<<row<<endl;
            }
            if(row==9)
            {
                break;
            }
        }while(1);
        
        return true;
        
    }
};

文章来源： https://blog.51cto.com/xiaohaiwa/5681457

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