leetcode

0 class Solution {

1 bool check(vector<vector<char>> &board, int i, int j, char val) {

2 for (int x = 0; x < 9; x++)

3 if (board[x][j] == val) return false;

4 for (int y = 0; y < 9; y++)

5 if (board[i][y] == val) return false;

6

7 i = (i / 3) * 3, j = (j / 3) * 3;

8 for (int x = i; x < i + 3; x++)

9 for (int y = j; y < j + 3; y++)

10 if (board[x][y] == val) return false;

11 return true;

12 }

13 bool solveSudoku(vector<vector<char>> &board, int i, int j) {

14 if (i == 9) return true;

15 if (j == 9) return solveSudoku(board, i + 1, 0);

16 if (board[i][j] != '.') return solveSudoku(board, i, j + 1);

17

18 for (char c = '1'; c <= '9'; c++) {

19 if (!check(board, i, j, c)) continue;

20 board[i][j] = c;

21 if (solveSudoku(board, i, j + 1)) return true;

22 board[i][j] = '.';

23 }

24

25 return false;

26 }

27

28 public:

29 void solveSudoku(vector<vector<char>> &board) { solveSudoku(board, 0, 0); }

30 };