leetcode 36. Valid Sudoku

class Solution {
public:
    bool isValidSudoku(vector<vector<char>>& board) {
        int check[10];
        for(int i = 0;i < 9;i++){
            memset(check,0,sizeof(check));
            for(int j = 0;j < 9;j++){
                if(board[i][j] == '.')continue;
                if(check[board[i][j]-'0'])return false;
                check[board[i][j]-'0'] = true;
            }
            memset(check,0,sizeof(check));
            for(int j = 0;j < 9; j++){
                if(board[j][i] == '.') continue;
                if(check[board[j][i]-'0'])return false;
                check[board[j][i]-'0'] = true;
            }
                
        }
        for(int i = 0;i < 3; i++){
            for(int j = 0;j < 3; j++){
                memset(check,0,sizeof(check));
                for(int k = 0;k < 3; k++){
                    for(int l = 0;l < 3; l++){
                        int x = i*3+k,y=j*3+l;
                        if(board[x][y] == '.') continue;
                        if(check[board[x][y]-'0'])return false;
                        check[board[x][y]-'0'] = true;
                        
                    }
                }
            }
        }
        return true;
    }
};