PTA_A1063

AC代码：

#include <iostream>
#include <cstdio>
#include <set>
using namespace std;

const long N=55;
set<long long> vi[N];
/*
void hanshu(int a,int b)
{
    int len = vi[a].size()+vi[b].size();

    set<long long>::iterator it;
    for(it = vi[a].begin();it != vi[a].end();it++){
        vt.insert(*it);
    }
    for(it = vi[b].begin();it != vi[b].end();it++){
        vt.insert(*it);
    }
    double nt = vt.size();
    
    vt.clear();

    double nc=len-nt;
    double str=nc/nt;
    printf("%.1lf%\n",str*100);
}
*/

void hanshu(int a, int b)
{
    int nt=vi[b].size(),nc=0;
    for(set<long long>::iterator it=vi[a].begin();it!=vi[a].end();it++){
        if(vi[b].find(*it) != vi[b].end())    nc++;
        else    nt++;
    }
    
    printf("%.1lf%\n",nc*100.0/nt);
}

int main(void)
{
    freopen("in.txt","r",stdin);
    
    int n,m,k;
    long long tmp;
    scanf("%d",&n);
    for(int i=0;i<n;i++){
        scanf("%d",&m);
        for(int j=0;j<m;j++){
            scanf("%lld",&tmp);
            vi[i+1].insert(tmp);
        }
    }
    
    scanf("%d",&k);
    for(int i=0;i<k;i++){
        int a,b;
        double count;
        scanf("%d%d",&a,&b);
        hanshu(a,b);    
        
    } 
    
    
    fclose(stdin);
    return 0;
}