求连通块的个数代码 dfs/并查集

dfs代码：

//求连通块的个数
#include<iostream>
#include<cstdio>
#include<vector>
#define maxn 1000
using namespace std;

vector<int> G[maxn];
bool vis[maxn] = {false};

int m, n;

void dfs(int v)
{
    vis[v] = true;
    for(int i = 0; i < G[v].size(); i++)
    {
        if(vis[G[v][i]] == false)
        {
            dfs(G[v][i]);
        }
    }
}


int main()
{
    scanf("%d %d",&m, &n);
    for(int i = 0; i < n; i++)
    {
        int a, b;
        scanf("%d %d", &a, &b);
        G[a].push_back(b);
        G[b].push_back(a);
    }

    int block = 0;
    for(int i = 1; i <= m; i++)
    {
        if(vis[i] == false)
        {
            dfs(i);
            block++;
        }
    }

    printf("%d", block);

    return 0;
}
//求连通块的个数
#include<iostream&