1272. NonYekaterinburg Subway 夜

http://acm.timus.ru/problem.aspx?space=1&num=1272

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<vector>

using namespace std;
const int INF=0x3f3f3f3f;
const int N=10005;
int f[N];
int findx(int x)
{
    if(f[x]!=x)
    f[x]=findx(f[x]);
    return f[x];
}
int main()
{
    int n,k,m;
    while(scanf("%d %d %d",&n,&k,&m)!=EOF)
    {
        for(int i=1;i<=n;++i)
        f[i]=i;
        while(k--)
        {
            int l,r;
            scanf("%d %d",&l,&r);
            f[findx(l)]=findx(r);
        }
        int ans=0;
        while(m--)
        {
            int l,r;
            scanf("%d %d",&l,&r);
            if(findx(l)!=findx(r))
            {++ans;f[findx(l)]=r;}
        }
        printf("%d\n",ans);
    }
    return 0;
}