1 class Solution {
2 public int islandPerimeter(int[][] grid) {
3 if(grid == null) return 0;
4 int row = grid.length;
5 if(row == 0) return 0;
6 int col = grid[0].length;
7 int res = 0;
8 for(int i = 0; i < row; i++) {
9 for(int j = 0; j < col; j++) {
10 if(grid[i][j] == 1) {
11 res += 4;
12 if(i+1 < row && grid[i+1][j] == 1) {
13 res -= 1;
14 }
15 if(i-1 >= 0 && grid[i-1][j] == 1) {
16 res -= 1;
17 }
18 if(j+1 < col && grid[i][j+1] == 1) {
19 res -= 1;
20 }
21 if(j-1 >= 0 && grid[i][j-1] == 1) {
22 res -= 1;
23 }
24 }
25 }
26 }
27 return res;
28
29 }
30 }
