CF1394D.Boboniu and Jianghu
省选/NOI-
通过率:0%
时间限制:1.00s
内存限制:256MB
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题目描述
Since Boboniu finished building his Jianghu, he has been doing Kungfu on these mountains every day.
Boboniu designs a map for his n mountains. He uses n−1 roads to connect all n mountains. Every pair of mountains is connected via roads.
For the i-th mountain, Boboniu estimated the tiredness of doing Kungfu on the top of it as ti. He also estimated the height of each mountain as hi.
A path is a sequence of mountains M such that for each i (1≤i<∣M∣), there exists a road between Mi and Mi+1. Boboniu would regard the path as a challenge if for each i (1≤i<∣M∣), hMi≤hMi+1.
Boboniu wants to divide all n−1 roads into several challenges. Note that each road must appear in exactly one challenge, but a mountain may appear in several challenges.
Boboniu wants to minimize the total tiredness to do all the challenges. The tiredness of a challenge M is the sum of tiredness of all mountains in it, i.e. ∑i=1∣M∣tMi.
He asked you to find the minimum total tiredness. As a reward for your work, you'll become a guardian in his Jianghu.
自从鲍伯牛建好他的江湖后,他每天都在这些山上练习功夫。
鲍伯牛为他的 n 座山设计了一张地图。他用 n−1 条道路将全部 n 座山连通,使得任意两座山之间都可通过道路相互到达。
对于第 i 座山,鲍伯牛估算了在其山顶练功的疲劳值 ti;同时,他也估算了每座山的高度 hi。
一条路径是一个山的序列 M,满足:对每个 i(1≤i<∣M∣),Mi 与 Mi+1 之间存在一条道路。若对每个 i(1≤i<∣M∣)均有 hMi≤hMi+1,则鲍伯牛将该路径视为一项挑战。
鲍伯牛希望将全部 n−1 条道路划分成若干项挑战。注意:每条道路必须且仅能出现在一项挑战中,但一座山可以出现在多项挑战中。
鲍伯牛希望最小化完成所有挑战所需的总疲劳值。一项挑战 M 的疲劳值定义为其中所有山的疲劳值之和,即 ∑i=1∣M∣tMi。
他请你求出最小总疲劳值。作为对你工作的嘉奖,你将成为他江湖中的一名守护者。
输入格式
The first line contains a single integer n (2≤n≤2⋅105), denoting the number of the mountains.
The second line contains n integers t1,t2,…,tn (1≤ti≤106), denoting the tiredness for Boboniu to do Kungfu on each mountain.
The third line contains n integers h1,h2,…,hn (1≤hi≤106), denoting the height of each mountain.
Each of the following n−1 lines contains two integers ui, vi (1≤ui,vi≤n,ui=vi), denoting the ends of the road. It's guaranteed that all mountains are connected via roads.
第一行包含一个整数 n(2≤n≤2⋅105),表示山的数量。
第二行包含 n 个整数 t1,t2,…,tn(1≤ti≤106),表示 Boboniu 在每座山上练习功夫所消耗的疲劳值。
第三行包含 n 个整数 h1,h2,…,hn(1≤hi≤106),表示每座山的高度。
接下来的 n−1 行中,每行包含两个整数 ui、vi(1≤ui,vi≤n,且 ui=vi),表示一条道路的两个端点。保证所有山通过道路相互连通。
输出格式
Print one integer: the smallest sum of tiredness of all challenges.
输出一个整数:所有挑战的疲劳度总和的最小值。
输入输出样例
输入#1
5 40 10 30 50 20 2 3 2 3 1 1 2 1 3 2 4 2 5
输出#1
160
输入#2
5 1000000 1 1 1 1 1000000 1 1 1 1 1 2 1 3 1 4 1 5
输出#2
4000004
输入#3
10 510916 760492 684704 32545 484888 933975 116895 77095 127679 989957 402815 705067 705067 705067 623759 103335 749243 138306 138306 844737 1 2 3 2 4 3 1 5 6 4 6 7 8 7 8 9 9 10
输出#3
6390572
说明/提示
For the first example:

In the picture, the lighter a point is, the higher the mountain it represents. One of the best divisions is:
- Challenge 1: 3→1→2
- Challenge 2: 5→2→4
The total tiredness of Boboniu is (30+40+10)+(20+10+50)=160. It can be shown that this is the minimum total tiredness.
对于第一个样例:

图中,一个点越亮,代表其对应的山越高。其中一种最优划分方式为:
- 挑战 1:3→1→2
- 挑战 2:5→2→4
鲍伯牛的总疲劳值为 (30+40+10)+(20+10+50)=160。可以证明这是最小的总疲劳值。
输入解题思路,AI测评打分。不知道怎么写?