题目

Given two sets of integers, the similarity of the sets is defined to be $N_{c} / N_{t} \times 100 \%,$ 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$N( \leq 50)$which is the total number of sets. Then N lines follow, each gives a set with a positive $M(\leq 10 ^ 4)$ 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:

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7

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:

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2

50.0%
33.3%

题解

思路

• Python的集合有交，并这些自带的函数
• So，你懂得。

数据结构

• sets 存放所有的集合
• a,b是要计算的两个集合

算法

• 使用自带的计算集合交并的方式。

代码

• 由于使用Python能AC，因此只放了Python的代码。

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sets = []
for _ in range(int(input())):
    sets.append(set(map(int, input().split()[1:])))
for _ in range(int(input())):
    a, b = list(map(lambda x: int(x) - 1, input().split()))
    print("%.1f%%" % ((len(sets[a] & sets[b]) / len(sets[a] | sets[b]))*100))