LeetCode第36题——valid sudoku

问题描述
Determine if a 9x9 Sudoku board is valid. Only the filled cells need to be validated according to the following rules:

Each row must contain the digits 1-9 without repetition.
Each column must contain the digits 1-9 without repetition.
Each of the 9 3x3 sub-boxes of the grid must contain the digits 1-9 without repetition.

解法思路
直接检验三个规则是否都符合

C++代码

class Solution {
public:
    bool isValidSudoku(vector<vector<char>>& board) {
        //直接验证三个规则
        for(int i=0;i<9;++i)
        {
            vector<int> number;
            for(int j=0;j<9;++j)
            {
                if(board[i][j]!='.')
                {
                    for(int k=0;k<number.size();++k)
                    {
                        if(board[i][j]==board[i][number[k]]) return false;
                      
                    }
                    number.push_back(j);
                }
            }
            vector<int> number2;
             for(int j=0;j<9;++j)
            {
                if(board[j][i]!='.')
                {
                    for(int k=0;k<number2.size();++k)
                    {
                        if(board[j][i]==board[number2[k]][i]) return false;
                    }
                    number2.push_back(j);
                }
            }
        }
        //检验sub-box
        for(int i=0;i<9;i=i+3)
        {
            for(int j=0;j<9;j=j+3)
            {
                vector<vector<int>> v;
                for(int k=i;k<i+3;++k)
                {
                    for(int m=j;m<j+3;++m)
                    {
                        if(board[k][m]!='.')
                        {
                            for(int a=0;a<v.size();++a)
                            {
                                if(board[k][m]==board[v[a][0]][v[a][1]]) return false;
                            }
                            v.push_back({k,m});
                        }
                    }
                }
            }
        }
        return true;
    }
};

算法结果
Runtime: 16 ms, faster than 96.32% of C++ online submissions for Valid Sudoku.
Memory Usage: 10.1 MB, less than 97.94% of C++ online submissions for Valid Sudoku.