PAT 1063 Set Similarity

Given two sets of integers, the similarity of the sets is defined to be N​c​​/N​t​​×100%, where N​c​​ is the number of distinct common numbers shared by the two sets, and N​t​​ is the total number of distinct numbers in the two sets. Your job is to calculate the similarity of any given pair of sets.

Input Specification:

Each input file contains one test case. Each case first gives a positive integer N (≤50) which is the total number of sets. Then N lines follow, each gives a set with a positive M (≤10​4​​) and followed by M integers in the range [0,10​9​​]. After the input of sets, a positive integer K (≤2000) is given, followed by K lines of queries. Each query gives a pair of set numbers (the sets are numbered from 1 to N). All the numbers in a line are separated by a space.

Output Specification:

For each query, print in one line the similarity of the sets, in the percentage form accurate up to 1 decimal place.

Sample Input:

3
3 99 87 101
4 87 101 5 87
7 99 101 18 5 135 18 99
2
1 2
1 3

Sample Output:

50.0%
33.3%

#include<cstdio>
#include<cstring>
#include<vector>
#include<set>
#include<algorithm>
using namespace std;

const int N=51;

set<int>st[N];
void cmp(int x,int y){
	int tot=st[x].size()+st[y].size(),sameNum=0;
	if(st[x].size()<=st[y].size()){
		for(set<int>::iterator it=st[x].begin();it!=st[x].end();it++){
			if(st[y].find(*it)!=st[y].end())	sameNum++;
		}	
	}
	else {
		for(set<int>::iterator it=st[y].begin();it!=st[y].end();it++){
			if(st[x].find(*it)!=st[x].end())	sameNum++;
		}
	}
	//printf("%d%d",tot,sameNum);
	printf("%.1f%%\n",sameNum*100.0/(tot-sameNum));
}

int main(){
	int n,k,q,v,st1,st2;
	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",&st1,&st2);
		cmp(st1,st2);
	}
	return 0;
}