岛屿数量

发布时间:2022-07-04 发布网站:脚本宝典
脚本宝典收集整理的这篇文章主要介绍了岛屿数量脚本宝典觉得挺不错的,现在分享给大家,也给大家做个参考。

题目链接:https://leetcode-cn.COM/PRoblems/number-of-islands 题目描述: 给你一个由 '1'(陆地)和 '0'(水)组成的的二维网格,请你计算网格中岛屿的数量。 岛屿总是被水包围,并且每座岛屿只能由水平方向和/或竖直方向上相邻的陆地连接形成。 此外,你可以假设该网格的四条边均被水包围。

示例 1: 输入:grid = [ ["1","1","1","1","0"], ["1","1","0","1","0"], ["1","1","0","0","0"], ["0","0","0","0","0"] ] 输出:1

示例 2: 输入:grid = [ ["1","1","0","0","0"], ["1","1","0","0","0"], ["0","0","1","0","0"], ["0","0","0","1","1"] ] 输出:3

提示: m == grid.length n == grid[i].length 1 <= m, n <= 300 grid[i][j] 的值为 '0' 或 '1'

题解:

class Solution {
public:
    int numIslands(vector<vector<char>>&amp; grid) {
       int ans = 0;
       for(int i = 0; i < grid.size(); i++)
       {
           for(int j = 0; j < grid[0].size(); j++)
           {
               if(grid[i][j] == '1')
               {
                   ans++; 
                   DFs(grid, i, j);
               }
           }
       }
       return ans;
    }
    void dfs(vector<vector<char>>& grid, int r, int c)
    {
        //base 判断是否越界
        if(!isLands(grid, r, c))
            return;
        if(grid[r][c] != '1')
            return;
        //标记已经访问过的点
        grid[r][c] = '2';
        //遍历周围点
        dfs(grid, r - 1, c);
        dfs(grid, r + 1, c);
        dfs(grid, r, c - 1);
        dfs(grid, r, c + 1);
    }
    bool isLands(vector<vector<char>>& grid, int r, int c)
    {
        return (r >= 0 && r < grid.size() && c >= 0 && c <grid[0].size());
    }
};

脚本宝典总结

以上是脚本宝典为你收集整理的岛屿数量全部内容,希望文章能够帮你解决岛屿数量所遇到的问题。

如果觉得脚本宝典网站内容还不错,欢迎将脚本宝典推荐好友。

本图文内容来源于网友网络收集整理提供,作为学习参考使用,版权属于原作者。
如您有任何意见或建议可联系处理。小编QQ:384754419,请注明来意。