Codeforces Round 665 (Div. 2)
D
Maximum Distributed Tree
Codeforces
1800
原题
← CE →
翻译中…

You are given a tree that consists of $n$ nodes. You should label each of its $n-1$ edges with an integer in such way that satisfies the following conditions:

翻译中…
  • each integer must be greater than $0$;
  • the product of all $n-1$ numbers should be equal to $k$;
  • the number of $1$-s among all $n-1$ integers must be minimum possible.
翻译中…

Let's define $f(u,v)$ as the sum of the numbers on the simple path from node $u$ to node $v$. Also, let $\sum\limits_{i=1}^{n-1} \sum\limits_{j=i+1}^n f(i,j)$ be a distribution index of the tree.

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Find the maximum possible distribution index you can get. Since answer can be too large, print it modulo $10^9 + 7$.

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In this problem, since the number $k$ can be large, the result of the prime factorization of $k$ is given instead.

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Input

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The first line contains one integer $t$ ($1 \le t \le 100$) — the number of test cases.

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The first line of each test case contains a single integer $n$ ($2 \le n \le 10^5$) — the number of nodes in the tree.

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Each of the next $n-1$ lines describes an edge: the $i$-th line contains two integers $u_i$ and $v_i$ ($1 \le u_i, v_i \le n$; $u_i \ne v_i$) — indices of vertices connected by the $i$-th edge.

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Next line contains a single integer $m$ ($1 \le m \le 6 \cdot 10^4$) — the number of prime factors of $k$.

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Next line contains $m$ prime numbers $p_1, p_2, \ldots, p_m$ ($2 \le p_i \lt 6 \cdot 10^4$) such that $k = p_1 \cdot p_2 \cdot \ldots \cdot p_m$.

翻译中…

It is guaranteed that the sum of $n$ over all test cases doesn't exceed $10^5$, the sum of $m$ over all test cases doesn't exceed $6 \cdot 10^4$, and the given edges for each test cases form a tree.

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Output

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Print the maximum distribution index you can get. Since answer can be too large, print it modulo $10^9+7$.

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Note

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In the first test case, one of the optimal ways is on the following image:

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image

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In this case, $f(1,2)=1$, $f(1,3)=3$, $f(1,4)=5$, $f(2,3)=2$, $f(2,4)=4$, $f(3,4)=2$, so the sum of these $6$ numbers is $17$.

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In the second test case, one of the optimal ways is on the following image:

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image

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In this case, $f(1,2)=3$, $f(1,3)=1$, $f(1,4)=4$, $f(2,3)=2$, $f(2,4)=5$, $f(3,4)=3$, so the sum of these $6$ numbers is $18$.

翻译中…

样例

Input #1
3
4
1 2
2 3
3 4
2
2 2
4
3 4
1 3
3 2
2
3 2
7
6 1
2 3
4 6
7 3
5 1
3 6
4
7 5 13 3
Output #1
17
18
286
InputCopy OutputCopy
题目信息
题号
1401D
时间限制
2 s
内存限制
256 MB
标签
DFS 及类似
动态规划
贪心
模拟
数学
数论
排序
树

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。