题意:求次小生成树,若权值和与最小生成树相等,输出"Not Unique!" :否则,输出mst /* 次小生成树 首先明白一点,次小生成树是由最小生成树改变一条边得来的,然后我们就可以先求出最小生成树, 然后枚举没在最小生成树中的边(x.y.z),用这条边来替换树中x.y之间的一条边,很显然,替换 时应该替换x.y中的最长边,所以可以预处理出树中x.y之间的最长边. */ #include<cstdio> #include<iostream> #include…

The Unique MST Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 24152   Accepted: 8587 Description Given a connected undirected graph, tell if its minimum spanning tree is unique. Definition 1 (Spanning Tree): Consider a connected, undire…

最小生成树的唯一性,部分参考了oi-wiki 如果一条不在最小生成树边集内的边,它可以替换一条在最小生成树边集内,且权值相等的边,那么最小生成树不是唯一的 同过kruskal来判断 考虑权值相等的边,记录有几条边是目前可以被选入的,和实际选入了几条边,如果不相同,则最小生成树不唯一 原因是如果出现这两个值不相等的情况,则一定出现了环,且这个环内至少有两条边权值相同 具体实现,用一个\(\text{tail}\)指针指向当前权值的最后一条边,当\(\text{i}>\text{tail}\)(也就…

题意:求解最小生成树的权值是否唯一,即要我们求次小生成树的权值两种方法求最小生成树,一种用prim算法, 一种用kruskal算法 一:用prim算法 对于给定的图,我们可以证明,次小生成树可以由最小生成树变换一边得到. 那么我们可以如下求给定图的次小生成树.首先,我们用prime算法求出图的最小生成树, 在这个过程中记录每条边是否用过,以及两个点之间最短路径上的最大权值F[i,j] F[i,j]可以如此求得,当加入点u的时候,并且u的父结点是v 那么对于已经在生成树中的节点x F[x,u] =…

The Unique MST 题目链接: http://acm.hust.edu.cn/vjudge/contest/124434#problem/J 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).…

The Unique MST Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 19941   Accepted: 6999 Description Given a connected undirected graph, tell if its minimum spanning tree is unique.  Definition 1 (Spanning Tree): Consider a connected, undir…

The Unique MST Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 23180   Accepted: 8235 Description Given a connected undirected graph, tell if its minimum spanning tree is unique.  Definition 1 (Spanning Tree): Consider a connected, undir…

The Unique MST Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 38430   Accepted: 14045 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 (Spanni…

The Unique MST Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 25203   Accepted: 8995 Description Given a connected undirected graph, tell if its minimum spanning tree is unique. Definition 1 (Spanning Tree): Consider a connected, undire…

The Unique MST                                                                        Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 24058   Accepted: 8546 Description Given a connected undirected graph, tell if its minimum spanning tre…