【PTA-A】1063 Set Similarity (25 分)（Set）

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<iostream>
#include<set>
#include<algorithm>
using namespace std;
const int N = 55;
set<int> st[N];

void compare(int a, int b) {
	int diff = st[b].size(), same = 0;
	for (set<int>::iterator it = st[a].begin(); it != st[a].end();it++){
		if (st[b].find(*it) != st[b].end())same++;
		else diff++;
	}
	printf("%.1f%%\n", same * 100.0 / diff);
}


int main() {
	int n,m,temp;
	scanf("%d", &n);
	for (int i = 1; i <= n; i++) {
		scanf("%d", &m);
		for (int j = 0; j < m; j++) {
			scanf("%d", &temp);
			st[i].insert(temp);
		}
	}
	int k,a,b;
	scanf("%d", &k);
	for (int i = 0; i < k; i++) {
		scanf("%d %d", &a, &b);
		compare(a, b);
	}
	return 0;
}