Go语言题解LeetCode463岛屿的周长示例详解

输入：grid = [[0,1,0,0],[1,1,1,0],[0,1,0,0],[1,1,0,0]]
输出：16
解释：它的周长是上面图片中的 16 个黄色的边

输入：grid = [[1]]
输出：4

输入：grid = [[1,0]]
输出：4

public class Solution {
    public int IslandPerimeter(int[][] grid) {
        int w = grid[0].Length;
        int h = grid.Length;
        int c = 0;
        int[][] g = new int[h + 2][];
        for (int i = 0; i < h + 2; i++)
        {
            g[i] = new int[w+2];
            for (int j = 0; j <w + 2; j++)
            {
                if (i == 0 || j == 0 || i == h + 1 || j == w + 1)
                    g[i][j] = 0;
                else
                    g[i][j] = grid[i - 1][j - 1];
            }
        }
        for (int i = 1; i < h + 1; i++)
        {
            for (int j = 1; j <w + 1; j++)
            {
                if (g[i][j] == 1)
                    c += 5 - g[i][j] - g[i - 1][j] - g[i + 1][j] - g[i][j - 1] - g[i][j + 1];
            }
        }
        return c;
    }
}