【PAT】1063. Set Similarity

#define LOCAL#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#include <cmath>#include <string>#include <vector>#include <set>using namespace std;const int N=51;set<int> st[N];int main(){    #ifdef LOCAL        freopen("data.in","r",stdin);        freopen("data.out","w",stdout);    #endif // LOCAL    int n,q,x,y,k,v;    scanf("%d",&n);    for(int i=1;i<=n;i++){        scanf("%d",&k);        for(int j=0;j<k;j++){            scanf("%d",&v);            st[i].insert(v);        }    }    scanf("%d",&q);    for(int i=0;i<q;i++){        scanf("%d%d",&x,&y);        int num=0,total=st[y].size();        for(set<int>::iterator it=st[x].begin();it!=st[x].end();it++){            if(st[y].find(*it)!=st[y].end()) num++;            else total++;        }        printf("%.1f%\n",num*100.0/total);    }    return 0;}