---
title: "L2-005 集合相似度"
created: 2025-11-28
tags:
  - 算法
---

# L2-005 集合相似度

## 题目 [L2-005 集合相似度](https://pintia.cn/problem-sets/994805046380707840/exam/problems/type/7?problemSetProblemId=994805070149828608&page=1)

![[image-0a2a3eae.png]]

## 思路分析

![[image-7962c11c.png]]

## 代码实现

```cpp
#include<bits/stdc++.h>

using namespace std;

#define endl '\n'

using ll = long long;

using ull = unsigned long long;

using PII = pair<int,int>;

using Pll = pair<ll,ll>;

int dx[4]={-1,0,1,0},dy[4]={0,1,0,-1};

const int inf = 0x3f3f3f3f;

int main()

{

	ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);

	int n;cin>>n;

	vector<unordered_set<int>> sets(n+1);

	for(int i=1;i<=n;i++){

		int m,num;

		cin>>m;

		while(m--){

			cin>>num;

			sets[i].insert(num);

		}

	}

	int k,a,b;cin>>k;

	while(k--){

		cin>>a>>b;

		auto A=sets[a];

		auto B=sets[b];

		int nc=0;

		for(auto x:A)	nc+=B.count(x);

		int nt = A.size() + B.size() - nc;

		printf("%.2f%%\n",nc*100.0/nt);

	}

	return 0;

 }
```

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## 视频讲解

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