C - Count Connected Components Editorial（并查集求连通分量个数）

AC：

#include<iostream>
#include<cstring>
using namespace std;
int father[1000];
int find(int x){
    while(father[x]!=-1) x=father[x];
    return x;
}
void Union(int a,int b){
    int fa=find(a),fb=find(b);
    if(fa!=fb){
        father[fa]=fb;
    }
}
int main() {
    int n,m;
    cin>>n>>m;
    memset(father,-1,sizeof(int)*(n+1));
    int a,b,ans=0;
    while(m--){
        cin>>a>>b;
        Union(a,b);
    }
    for(int i=1;i<=n;i++){
        if(father[i]==-1) ans++;
    }
    cout<<ans<<endl;

    return 0;
}