Cover Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1543    Accepted Submission(s): 321Special Judge Problem Description The Wall has down and the King in the north has to send his soldiers to…

题目链接:http://poj.org/problem?id=1422 Consider a town where all the streets are one-way and each street leads from one intersection to another. It is also known that starting from an intersection and walking through town's streets you can never reach t…

先说说最小路径覆盖的定义 定义:在一个有向图中,找出最少的路径,使得这些路径,经过每一个点,且每一个点只与一条路径相关联, 由上面得出: 1.一个单独的点是一个路径 2:如果有路径a,b,c....f,g.a为起点,g为终点.那么a到g的点不在与其他点之间存在有向边. 最小路径覆盖=点数---最大匹配数 证明:1  如果匹配数为0,那么图中没有边,需要n条路径 2  如果a,b之间连一条边,那么匹配数增1,需要的路径数会减少一,因为a,b之间只需要一条,那么就证明了 #include<cstdi…

Antenna Placement Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 6991   Accepted: 3466 Description The Global Aerial Research Centre has been allotted the task of building the fifth generation of mobile phone nets in Sweden. The most st…

Girls and Boys Time Limit: 20000/10000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 6942    Accepted Submission(s): 3118 Problem Description the second year of the university somebody started a study on the romant…

题意 给个无向图,无重边和自环,问最少需要多少路径把边覆盖了.并输出相应路径 分析 首先联通块之间是独立的,对于一个联通块内,最少路径覆盖就是  max(1,度数为奇数点的个数/2).然后就是求欧拉路径了,先将块内度数为奇数的点找出来,留下两个点,其余两两连上虚边,这样我们选择从一个奇数点出发到另一个奇数点,求出一条欧拉路径,统计总路径数.接着就dfs,注意一些细节. 附赠一个求欧拉回路的fleury算法:https://blog.csdn.net/u011466175/article/deta…

HDU 6311 Cover (无向图最小路径覆盖) Time Limit: 6000/3000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1967 Accepted Submission(s): 442 Special Judge Problem Description The Wall has down and the King in the north has to sen…

题目: Air Raid Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 124 Accepted Submission(s): 102   Problem Description Consider a town where all the streets are one-way and each street leads from one…

http://acm.hdu.edu.cn/showproblem.php?pid=1151 Air Raid Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 7469   Accepted: 4451 Description Consider a town where all the streets are one-way and each street leads from one intersection to an…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=3861 最小路径覆盖的一篇博客:https://blog.csdn.net/qq_39627843/article/details/82012572 题意: 把城市至少分成几个块,规则有三 1. A能B,B能到A,那么A,B一定要在一起. 2. 一个城市只能属于一个块. (说明了是最小不相交覆盖)3. 在一个块里的城市,任意2点之间必须有路径. 对于规则1,就是说强连通的必须在一起,所以用Tarjan…