LeetCode: Island Perimeter

public class Solution {
    public int islandPerimeter(int[][] grid) {
        int ans = 0;
        for (int i = 0; i < grid.length; i++) {
            for (int j = 0; j < grid[0].length; j++) {
                if (grid[i][j] == 1) {
                    if (i == 0 || (i > 0 && grid[i-1][j] == 0)) ans++;  //top
                    if (i == grid.length-1 || (i < grid.length-1 && grid[i+1][j] == 0)) ans++; //bottom
                    if (j == 0 || (j > 0 && grid[i][j-1] == 0)) ans++; //left
                    if (j == grid[0].length-1 || (j < grid[0].length-1 && grid[i][j+1] == 0)) ans++; //right
                }
            }
        }
        return ans;
    }
}