华南理工大学“三七互娱杯”程序设计竞赛（重现赛）G HRY and tree

最新推荐文章于 2019-04-29 20:48:11 发布

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最新推荐文章于 2019-04-29 20:48:11 发布 · 311 阅读

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本文介绍了一道编程竞赛题，涉及到GDCPC地铁线路的模型，其中线路被视为由n个点和n-1条边组成的连通图。每条边的权重代表两点之间的距离，路径权重定义为简单路径上最大边权重。题目要求计算所有点对之间的路径权重之和。解题思路是按边权从小到大排序，依次计算每条边对总和的贡献，即两端点连通块大小乘以边权。

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链接：https://ac.nowcoder.com/acm/contest/874/G
来源：牛客网

题目描述

In 9102, HRY was elected as the director of the GDCPC Metro Bureau. In his work, he needs to use his knowledge to solve some problems.
The subway line of GDCPC can be regarded as a connected graph composed of n points and n-1 edges. The edge weight represents the distance between two points. The weight of the path between two different points is defined as the maximum value of the edge weights of all edges on the simple path between them. Now HRY needs to know the sum of the weights of all pairs of points (obviously there are C2nCn2 kinds), because he is busy, so he wants you, a JBer, to helped him calculate it.

输入描述:

The first line of the input file contains a positive integer T, indicating the number of test cases.
Each case has n lines. The first line is a positive integer n, indicating the number