1063 Set Similarity-PAT甲级

题目描述

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

 

输入描述:

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 (<=104) and followed by M integers in the range [0, 109].  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.

 

输出描述:

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

 

输入例子:

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

 

输出例子:

50.0%
33.3%

注意：在使用set_union()和set_intersection()函数时，如果选用的时vector数组作前4个参数，则左后的结果也会保留重复的元素，如果选择set，则不会保留重复的元素，注意区别

#include<bits/stdc++.h>
using namespace std;
const int N=10010;
set<int>st[N];
vector<int>ve;
int n,q;
int main(){
	cin.tie(0);
	cout.tie(0);
	cin>>n;
	for(int i=1;i<=n;i++){
		int sum,x;
		cin>>sum;
		for(int j=1;j<=sum;j++){
			cin>>x;
			st[i].insert(x);
		}
	}
	cin>>q;
	int a,b;
	for(int i=1;i<=q;i++){
		cin>>a>>b;
		ve.clear();
		set_intersection(st[a].begin(),st[a].end(),st[b].begin(),st[b].end(),inserter(ve,ve.begin()));
		int k1=ve.size();
		ve.clear();
		set_union(st[a].begin(),st[a].end(),st[b].begin(),st[b].end(),inserter(ve,ve.begin()));
		int k2=ve.size();
		printf("%.1f%\n",k1*1.0/k2*100);
	}
	return 0;
}