leetcode

0 class Solution {

1 public:

2 int islandPerimeter(const vector<vector<int>> &grid) const {

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

4 static int offset[] = {-1, 0, 1, 0, -1};

5 int res = 0;

6

7 for (int i = 0; i < n; i++) {

8 for (int j = 0; j < m; j++) {

9 if (!grid[i][j]) continue;

10

11 res += 4;

12 for (int k = 0; k < 4; k++) {

13 const int x = i + offset[k];

14 const int y = j + offset[k + 1];

15 if (x < 0 || y < 0 || x >= n || y >= m) continue;

16 res -= grid[x][y] == 1;

17 }

18 }

19 }

20

21 return res;

22 }

23 };