题意: 构造题,节点1~n顺时针排列成圆形,告诉你每个点度数奇偶性,让你构造一棵树,树边不相交. 思路: 因为每条边给总度数贡献2,因此如果度数为1的点有奇数个,直接输出no.显然0个度数为1的,也输出no. 找到每个1,把1往后的部分分到一组,第二组的最后一个连第一组的最后一个,然后3组往后的最后一个连第一组的第一个(1). code: #include<bits/stdc++.h> using namespace std; const int N=1e6+5; char s[N]; int…

题意 1-n排列,构成一个圆:1-n每个点有个值0或者1,0代表点的度为偶数,1代表点的度为计数:询问能否构成一棵树,树的连边在圆内不会相交,在圆边上可以相交,可以则输出方案. 提示 1. 首先考虑什么时候无解,显然,奇数点个数是偶数,并且>=2 2. 由奇数点个数为偶数可以发现,它们可以连到同一个偶数点上(并非直接连) 3. 剩下的偶数点可以直接顺时针串联,直到连到最近的一个奇数点上 4. 相当于每个奇数点后面有一条偶数链,或者没有偶数链只有一个奇点(这都是一样的,因为链最后一个点都只剩下一个…

Problem Description XXX is very interested in algorithm. After learning the Prim algorithm and Kruskal algorithm of minimum spanning tree, XXX finds that there might be multiple solutions. Given an undirected weighted graph with n (1<=n<=100) vertex…

给定一个无向图,如果他的某个子图中,任意两个顶点都能互相连通并且是一棵树,那么这棵树就叫做生成树(spanning tree). 如果边上有权值,那么使得边权和最小的生成树叫做最小生成树(MST,Minimum Spanning Tree).       1.prim版本的算法   .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", co…

E. Minimum spanning tree for each edge   Connected undirected weighted graph without self-loops and multiple edges is given. Graph contains n vertices and m edges. For each edge (u, v) find the minimal possible weight of the spanning tree that contai…

time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Connected undirected weighted graph without self-loops and multiple edges is given. Graph contains n vertices and m edges. For each edge (u,…

E. Minimum spanning tree for each edge time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Connected undirected weighted graph without self-loops and multiple edges is given. Graph contains n …

E. Minimum spanning tree for each edge 题目连接: http://www.codeforces.com/contest/609/problem/E Description Connected undirected weighted graph without self-loops and multiple edges is given. Graph contains n vertices and m edges. For each edge (u, v) f…

You may refer to the main idea of MST in graph theory. http://en.wikipedia.org/wiki/Minimum_spanning_tree Here is my own interpretation What is Minimum Spanning Tree? Given a connected and undirected graph, a spanning tree of that graph is a subgraph…

Minimum Spanning Tree Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) [Problem Description] XXX is very interested in algorithm. After learning the Prim algorithm and Kruskal algorithm of minimum spanning tree, XXX…