Leetcode-463 Island Perimeter

最新推荐文章于 2022-10-28 18:08:21 发布

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最新推荐文章于 2022-10-28 18:08:21 发布

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原文链接：http://www.cnblogs.com/fengxw/p/6184527.html

本文介绍了一个二维网格中计算岛屿周长的方法。通过遍历每个单元格，检查与水相邻的边界来确定岛屿的周长。文章提供了一段C++代码实现，展示了如何有效地计算出给定网格中岛屿的总周长。

#463.　Island Perimeter

　　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:

class Solution {
public:
    int islandPerimeter(vector<vector<int>>& grid) {
        int ret=0;
        int row=grid.size(),col=grid[0].size();
        for(int i=0;i<row;i++)
            for(int j=0;j<col;j++)
            {
                if(grid[i][j]==0)
                continue;
                if(i==0||grid[i-1][j]==0)ret++;
                if(i==row-1||grid[i+1][j]==0) ret++;
                if(j==0||grid[i][j-1]==0) ret++;
                if(j==col-1||grid[i][j+1]==0) ret++;
            }
        return ret;
    }
};

转载于:https://www.cnblogs.com/fengxw/p/6184527.html