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…

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…

The Unique MST Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 22668   Accepted: 8038 Description Given a connected undirected graph, tell if its minimum spanning tree is unique. Definition 1 (Spanning Tree): Consider a connected, undire…

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…

The Unique MST 时间限制: 10 Sec  内存限制: 128 MB提交: 25  解决: 10[提交][状态][讨论版] 题目描述 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 tre…

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…

无向连通图(无重边),判断最小生成树是否唯一,若唯一求边权和. 分析生成树的生成过程,只有一个圈内出现权值相同的边才会出现权值和相等但“异构”的生成树.(并不一定是最小生成树) 分析贪心策略求最小生成树的过程(贪心地选最短的边来扩充已加入生成树的顶点集合U),发现只有当出现“U中两个不同的点到V-U中同一点的距离同时为当前最短边”时,才会出现“异构”的最小生成树. 上图为kruscal和prim生成过程中可能遇到的相等边的情况,红色和蓝色的为权值相等的边. 可以看到kruscal由于事先将所有边…

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…