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POJ 2485 Highways C语言版 Kruskal

POJ题解 Slyar 85浏览 0评论

文章作者:姜南(Slyar) 文章来源:Slyar Home (www.slyar.com) 转载请注明,谢谢合作。

Kruskal算法的应用

Description

The island nation of Flatopia is perfectly flat. Unfortunately, Flatopia has no public highways. So the traffic is difficult in Flatopia. The Flatopian government is aware of this problem. They're planning to build some highways so that it will be possible to drive between any pair of towns without leaving the highway system.

Flatopian towns are numbered from 1 to N. Each highway connects exactly two towns. All highways follow straight lines. All highways can be used in both directions. Highways can freely cross each other, but a driver can only switch between highways at a town that is located at the end of both highways.

The Flatopian government wants to minimize the length of the longest highway to be built. However, they want to guarantee that every town is highway-reachable from every other town.

Input

The first line of input is an integer T, which tells how many test cases followed.
The first line of each case is an integer N (3 <= N <= 500), which is the number of villages. Then come N lines, the i-th of which contains N integers, and the j-th of these N integers is the distance (the distance should be an integer within [1, 65536]) between village i and village j. There is an empty line after each test case.

Output

For each test case, you should output a line contains an integer, which is the length of the longest road to be built such that all the villages are connected, and this value is minimum.

Sample Input

1

3
0 990 692
990 0 179
692 179 0

Sample Output

692

Slyar:题意很简单,就是给你t组数据,每组数据给你一个n,然后下面是n*n的无向图邻接矩阵表示,求最小生成树的最大边权。

看到边数目不是很多,而且是无向图,考虑使用Kruskal算法,读入数据只取上三角即可。

最近写最小生成树的题写到想吐了...没想到推荐题目第一道又是最小生成树,囧...

转载请注明:Slyar Home » POJ 2485 Highways C语言版 Kruskal

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