PTA:7-129 文件传输 (25分)–(并查集)

#include<bits/stdc++.h>
using namespace std;
int n,p[10009];
int find(int x){
    if(x==p[x]) return x;
    return p[x]=find(p[x]);
}

void merge(int x, int y){
    int xx=find(x), yy=find(y);
    if(xx!=yy) p[xx]=yy; 
}

int main(){
    cin>>n;
    for(int i=1; i<=n; i++) p[i]=i;
    getchar;
    char ch='a';
    int a,b;
    while(1){
        cin>>ch;
        if(ch=='S') break;
        cin>>a>>b;
        if(ch=='C'){
            if(find(a)==find(b)) cout<<"yesn";
            else cout<<"non";
        }else if(ch=='I'){
            merge(a,b);
        }
    }
    int cnt=0;
    for(int i=1; i<=n; i++){
        if(i==find(i)) cnt++;
    }
    if(cnt==1) cout<<"The network is connected.n";
    else cout<<"There are "<<cnt<<" components.n";
    return 0;
}