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5631:Rikka with Graph

题目描述
As we know, Rikka is poor at math. Yuta is worrying about this situation, so he gives Rikka some math tasks to practice. There is one of them:

Yuta has a non-direct graph with n vertices and n+1 edges. Rikka can choose some of the edges (at least one) and delete them from the graph.

Yuta wants to know the number of the ways to choose the edges in order to make the remaining graph connected.

It is too difficult for Rikka. Can you help her?
输入解释
The first line contains a number $T(T \leq 30)$——The number of the testcases.

For each testcase, the first line contains a number $n(n \leq 100)$.

Then n+1 lines follow. Each line contains two numbers $u,v$ , which means there is an edge between u and v.
输出解释
For each testcase, print a single number.
输入样例
1
3
1 2
2 3
3 1
1 3
输出样例
9
来自杭电HDUOJ的附加信息
Recommend hujie

该题目是Virtual Judge题目,来自 杭电HDUOJ

源链接: HDU-5631

最后修改于 2020-10-25T23:24:21+00:00 由爬虫自动更新

共提交 0

通过率 --%
时间上限 内存上限
2000/1000MS(Java/Others) 65536/65536K(Java/Others)