斯坦纳树,$dp$. 先求出每个状态下连通的最小花费,因为可以是森林,所以$dp$一下. #include<bits/stdc++.h> using namespace std; int n; const int INF = 0x7FFFFFFF; struct X { int p,s,q; }e[]; ]; vector<]; ][],d[][],dp[]; *],k; queue<int>Q; ],cost[]; void spfa() { while(!Q.empty(…

题目链接: https://vjudge.net/problem/ZOJ-1456 These are N cities in Spring country. Between each pair of cities there may be one transportation track or none. Now there is some cargo that should be delivered from one city to another. The transportation f…

http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=1456 题意:求最短路并且输出字典序最小的答案. 思路:如果用dijkstra来做的话,会比较麻烦,这里直接用floyd会简单的多,只需要记录好后继路径即可. #include<iostream> #include<algorithm> #include<cstring> #include<cstdio> #include<sst…

比赛链接: http://acm.hust.edu.cn/vjudge/contest/view.action?cid=44704#overview 题目来源: ZOJ Monthly, June 2012 on June 24 Wine93有话说: 无话可说~~~ 转下wuyiqi巨巨的题解:http://www.cnblogs.com/wuyiqi/archive/2012/06/25/2562806.html     ID Origin Title   6 / 27 Problem A Z…

上图论课的时候无意之间看到了这个,然后花了几天的时间学习了下,接下来做一个总结. 一般斯坦纳树问题是指(来自百度百科): 斯坦纳树问题是组合优化问题,与最小生成树相似,是最短网络的一种.最小生成树是在给定的点集和边中寻求最短网络使所有点连通.而最小斯坦纳树允许在给定点外增加额外的点,使生成的最短网络开销最小. 然后听说已经被证明为是NP问题了,在ACM竞赛中我们不研究这个,我们研究更简单一些的问题. 对于图G(V,E),其中V表示图中点集,E表示图中边集.设A是V的某个子集,求至少包含A中所有点…

迪杰斯特拉最短路径. 1.every city must wait till all the goods arrive, and then transport the arriving goods together with its own goods to the next city.  这个条件貌似可以忽略掉. 2.One city can only transport the goods to one city.  这个条件貌似也可以忽略掉,是一定的. 例如:A物品和B物品在不同的城市,他…

题目: 有N-1个城市给首都(第N个城市)支援物资,有M条路,走每条路要耗费一定百分比(相对于这条路的起点的物资)的物资.问给定N-1个城市将要提供的物资,和每条路的消耗百分比.求能送到首都的最多的物资数量. 思路: 可以将这条路的对物资的消耗百分比转换为走过后留下的百分比,然后对这些路跑最长路. #include <bits/stdc++.h> #include <cstdio> #include <cstring> #include <iostream>…

转自——http://blog.csdn.net/qwe20060514/article/details/8112550 =============================以下是最小生成树+并查集======================================[HDU]1213   How Many Tables   基础并查集★1272   小希的迷宫   基础并查集★1325&&poj1308  Is It A Tree?   基础并查集★1856   More i…

Conquer a New Region Time Limit: 8000/4000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 657 Accepted Submission(s): 179 Problem Description The wheel of the history rolling forward, our king conquered a new region i…

POJ 1459 Power Network / HIT 1228 Power Network / UVAlive 2760 Power Network / ZOJ 1734 Power Network / FZU 1161 (网络流,最大流) Description A power network consists of nodes (power stations, consumers and dispatchers) connected by power transport lines. A…