LeetCode: 463 Island Perimeter(easy)

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本文介绍了一个算法问题，即计算二维网格中岛屿的周长。网格由1和0组成，1代表陆地，0代表水域。文章提供了一段C++代码，通过遍历网格来计算与水相邻的陆地边界，从而得出岛屿的总周长。

题目：

You are given a map in form of a two-dimensional integer grid where 1 represents land and 0 represents water. Grid cells are connected horizontally/vertically (not diagonally). The grid is completely surrounded by water, and there is exactly one island (i.e., one or more connected land cells). The island doesn't have "lakes" (water inside that isn't connected to the water around the island). One cell is a square with side length 1. The grid is rectangular, width and height don't exceed 100. Determine the perimeter of the island.

Example:

[[0,1,0,0],
 [1,1,1,0],
 [0,1,0,0],
 [1,1,0,0]]

Answer: 16
Explanation: The perimeter is the 16 yellow stripes in the image below:

代码:

循环遍历就好了~

class Solution {
public:
    int islandPerimeter(vector<vector<int>>& grid) {
        int result = 0;
        int n = grid.size();
        int m = grid[0].size();
        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                if(grid[i][j] == 1){
                    if(i==0 || grid[i-1][j] == 0) result++;
                    if(i==n-1 || grid[i+1][j] == 0) result++;
                    if(j==0 || grid[i][j-1] == 0) result++;
                    if(j==m-1 || grid[i][j+1] == 0) result++;
                }
            }
        }
        return result;
    }
};