寄存一下

#include<iostream>
#include<algorithm>
#include<string.h>
using namespace std;
#define MAXN 10050

int par[MAXN];
int ran[MAXN];
int n,m;
void init()
{
    for(int i=1;i<=100005;i++){
        par[i]=i;
        ran[i]=1;
    }
}

int find(int x){
    if(x==par[x]) return x;
    return x=find(par[x]);
}

void unite(int x,int y)
{
    x=find(x);
    y=find(y);
    if(x==y) return ;
    if(ran[x]<ran[y]){
        par[x]=y;
    }
    else{
        par[y]=x;
        if(ran[x]==ran[y]) ran[x]++;
    }
}

struct edge
{
    int u,v,cost;
}e[MAXN];
bool same(int a,int b){return find(a)==find(b);}

bool cmp(edge a,edge b)
{
    return a.cost<b.cost;
}
int main()
{
    int a,b;
    while(cin>>a>>b){
        init();
        memset(e,0,sizeof(e));
        if(a==b&&a==-1) return 0;
        e[0].u=a;
        e[0].v=b;
        int k=1;
        while(cin>>a>>b&&a&&b){
            e[k++].u=a;
            e[k++].v=b;
        }
        cout<<k<<endl;
        sort(e,e+k,cmp);
        int res=0;
        for(int i=0;i<k;i++){
            a=e[i].u;
            b=e[i].v;
            if(!same(a,b)){
                unite(a,b);
                res++;
            }
        }
        if(res==k+1) cout<<"Yes"<<endl;
        else cout<<"No"<<endl;
    }
    return 0;
}