0036.cpp

#include <vector>
using namespace std;

static int x = [](){std::ios::sync_with_stdio(false);cin.tie(0);return 0;}();
class Solution 
{
public:
    bool isValidSudoku(vector<vector<char>>& board) 
    {
        bool rows[9][9] = {false};
        bool cols[9][9] = {false};
        bool boxes[9][9] = {false};
        
        for (int i = 0; i < 9; ++i) 
        {
            for (int j = 0; j < 9; ++j) 
            {
                if (board[i][j] == '.') continue;
                
                int num = board[i][j] - '1';
                
                int k = i / 3 * 3 + j / 3;
                if (rows[i][num] or cols[j][num] or boxes[k][num]) return false;
                rows[i][num] = cols[j][num] = boxes[k][num] = true;
            }
        }
        return true;
    }
};