http://poj.org/problem?id=1679 题目大意: 给你一些点,判断MST(最小生成树)是否唯一. 思路: 以前做过这题,不过写的是O(n^3)的,今天学了一招O(n^2)的,哈哈~ 方法一: 首先先建立MST,然后把这个MST的边一个个尝试不使用,构建另外一颗MST,然后判断权值是否相等. 这样复杂度需要O(n^3).. 方法二: 还可以用次最小生成树的方法解决:如果最小生成树不唯一,那么次小生成树的权值和最小生成树相同. 我们可以枚举要加入哪一条新边.在最小生成树上加一…

题目:poj 1679 The Unique MST 题意:给你一颗树,让你求最小生成树和次小生成树值是否相等. 分析:这个题目关键在于求解次小生成树. 方法是,依次枚举不在最小生成树上的边,然后加入到最小生成树上,然后把原树上加入了之后形成环的最长的边删去,知道一个最小的.就是次小生成树. 这些须要的都能够在求解最小生成树的时候处理出来. AC代码: #include <cstdio> #include <cstring> #include <iostream> #i…

题目连接 http://poj.org/problem?id=1679 The Unique MST Description Given a connected undirected graph, tell if its minimum spanning tree is unique. Definition 1 (Spanning Tree): Consider a connected, undirected graph G = (V, E). A spanning tree of G is a…

http://poj.org/problem?id=1679 The Unique MST Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 17726   Accepted: 6150 Description Given a connected undirected graph, tell if its minimum spanning tree is unique. Definition 1 (Spanning Tree…

题目链接:http://poj.org/problem?id=1679 The Unique MST Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 29408   Accepted: 10520 Description Given a connected undirected graph, tell if its minimum spanning tree is unique. Definition 1 (Spannin…

题目地址:http://poj.org/problem?id=1679 2 3 3 1 2 1 2 3 2 3 1 3 4 4 1 2 2 2 3 2 3 4 2 4 1 2 Sample Output 3 Not Unique! 次小生成树学习博客:http://blog.csdn.net/niushuai666/article/details/6925258 分析:T组数据,每组n个节点m条边.计算一下,最小生成树是不是独一无二的,如果是就输出最小生成树的权值和,否则输出Not Unique…

题目链接:http://poj.org/problem?id=1679 题意: 给你一个图,问你这个图的最小生成树是否唯一. 题解: 求这个图的最小生成树和次小生成树.如果相等,则说明不唯一. 次小生成树(倍增算法): maxn[k][i]:表示从节点i向上走2^k步,这一段中边权的最大值. 枚举每一条不在MST中的边,求出这条边两端点之间在MST上路径上的最大边权mx. 次小生成树(非严格) = max(MST - mx + len) AC Code: #include <iostream>…

The Unique MST Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 22715   Accepted: 8055 Description Given a connected undirected graph, tell if its minimum spanning tree is unique.  Definition 1 (Spanning Tree): Consider a connected, undir…

Description Given a connected undirected graph, tell if its minimum spanning tree is unique.  Definition 1 (Spanning Tree): Consider a connected, undirected graph G = (V, E). A spanning tree of G is a subgraph of G, say T = (V', E'), with the followi…

题目链接: http://poj.org/problem?id=1679 Description Given a connected undirected graph, tell if its minimum spanning tree is unique. Definition 1 (Spanning Tree): Consider a connected, undirected graph G = (V, E). A spanning tree of G is a subgraph of G…