leetcode

0 class Solution {

1 public:

2 bool checkValidGrid(const vector<vector<int>> &grid) const {

3 static const int offset_x[] = {-2, -2, -1, -1, 1, 1, 2, 2};

4 static const int offset_y[] = {-1, 1, -2, 2, -2, 2, -1, 1};

5 const int n = size(grid), m = size(grid[0]);

6

7 int x = 0, y = 0;

8 if (grid[0][0] != 0) return false;

9 for (int cnt = 1; cnt < n * m; cnt++) {

10 for (int k = 0; k < 8; k++) {

11 const int a = x + offset_x[k];

12 const int b = y + offset_y[k];

13 if (a < 0 || b < 0 || a >= n || b >= m) continue;

14 if (grid[a][b] == cnt) {

15 x = a, y = b;

16 goto next;

17 }

18 }

19 return false;

20 next:;

21 }

22 return true;

23 }

24 };