bool isValidSudoku(vector<vector<char>>& board) 
{
        int row[9][9] = {0}, col[9][9] = {0}, box[9][9] = {0};
        for (int i = 0; i != board.size(); ++i)
        {
            for (int j = 0; j != board[i].size(); ++j)
            {
                if (board[i][j] != '.')
                {
                    int num = board[i][j] - '0' - 1;
                    int k = i / 3 * 3 + j / 3;
                    if (row[i][num] || col[j][num] || box[k][num])
                        return false;
                    row[i][num] = col[j][num] = box[k][num] = 1;
                }
            }
        }
	return true;
}