Farthest Nodes in a Tree Time Limit: 2000MS Memory Limit: 32768KB 64bit IO Format: %lld & %llu Submit Status Description Given a tree (a connected graph with no cycles), you have to find the farthest nodes in the tree. The edges of the tree are weigh…

1094 - Farthest Nodes in a Tree PDF (English) Statistics Forum Time Limit: 2 second(s) Memory Limit: 32 MB Given a tree (a connected graph with no cycles), you have to find the farthest nodes in the tree. The edges of the tree are weighted and undire…

http://lightoj.com/volume_showproblem.php?problem=1094 Given a tree (a connected graph with no cycles), you have to find the farthest nodes in the tree. The edges of the tree are weighted and undirected. That means you have to find two nodes in the t…

http://lightoj.com/volume_showproblem.php?problem=1094 树的直径是指树的最长简单路. 求法: 两遍BFS :先任选一个起点BFS找到最长路的终点,再从终点进行BFS,则第二次BFS找到的最长路即为树的直径: 原理: 设起点为u,第一次BFS找到的终点v一定是树的直径的一个端点 证明: 1) 如果u 是直径上的点,则v显然是直径的终点(因为如果v不是的话,则必定存在另一个点w使得u到w的距离更长,则于BFS找到了v矛盾)2) 如果u不是直径上的…

http://acm.hust.edu.cn/vjudge/contest/121398#problem/H 不是特别理解,今天第一次碰到这种问题.给个链接看大神的解释吧 http://www.cnblogs.com/qq2424260747/p/4740347.html #include <cstdio> #include <cstring> #include <iostream> #include <cmath> #include<vector&g…

1094 - Farthest Nodes in a Tree problem=1094" style="color:rgb(79,107,114)"> problem=1094&language=english&type=pdf" style="color:rgb(79,107,114)">PDF (English) Statistics Forum Time Limit: 2 second(s) Memory Li…

Roads in the North Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 2359   Accepted: 1157 Description Building and maintaining roads among communities in the far North is an expensive business. With this in mind, the roads are build such…

Cow Marathon Time Limit: 2000MS   Memory Limit: 30000K Total Submissions: 4185   Accepted: 2118 Case Time Limit: 1000MS Description After hearing about the epidemic of obesity in the USA, Farmer John wants his cows to get more exercise, so he has com…

题目链接:http://poj.org/problem?id=2631 题意:给出一棵树的两边结点以及权重,就这条路上的最长路. 思路:求实求树的直径. 这里给出树的直径的证明: 主要是利用了反证法: 假设 s-t这条路径为树的直径,或者称为树上的最长路 现有结论,从任意一点u出发搜到的最远的点一定是s.t中的一点,然后在从这个最远点开始搜,就可以搜到另一个最长路的端点,即用两遍广搜就可以找出树的最长路 证明:   1.设u为s-t路径上的一点,结论显然成立,否则设搜到的最远点为T则   dis…

1094 - Farthest Nodes in a Tree   PDF (English) Statistics Forum Time Limit: 2 second(s) Memory Limit: 32 MB Given a tree (a connected graph with no cycles), you have to find the farthest nodes in the tree. The edges of the tree are weighted and undi…