Friendship Time Limit: 2000MS   Memory Limit: 20000K Total Submissions: 11429   Accepted: 3173 Description In modern society, each person has his own friends. Since all the people are very busy, they communicate with each other only by phone. You can…

Friendship Time Limit: 2000MS   Memory Limit: 20000K Total Submissions: 8025   Accepted: 2224 Description In modern society, each person has his own friends. Since all the people are very busy, they communicate with each other only by phone. You can…

Friendship Time Limit: 2000MS   Memory Limit: 20000K Total Submissions: 10744   Accepted: 2984 Description In modern society, each person has his own friends. Since all the people are very busy, they communicate with each other only by phone. You can…

Description In modern society, each person has his own friends. Since all the people are very busy, they communicate with each other only by phone. You can assume that people A can keep in touch with people B, only if  1. A knows B's phone number, or…

(点击此处查看原题) 题目分析 题意:有n个人,编号记为1~n,n个人之间可能有人可以互相联系,如果A能和B联系,那么至少满足这两种情况之一:(1)A知道B的电话(2)A可以和C联系,并且C可以和B联系: 因为某些人可能会丢失他的手机,导致他失去所有人的号码以及其他人手机中他的号码,也就是说这个人无法和任何人联系了: 此时给出两个人s,t,问至少有多少人失去他们的手机,可以使得这两个人s,t无法联系. 答案输出最少需要的人数以及失去手机的人的编号,如果存在多组解,输出字典序小的那一组. 思路:平…

http://poj.org/problem?id=1815 题意: 在现代社会,每个人都有自己的朋友.由于每个人都很忙,他们只通过电话联系.你可以假定A可以和B保持联系,当且仅当:①A知道B的电话号码:②A知道C的电话号码,而C能联系上B.如果A知道B的电话号码,则B也知道A的电话号码. 思路:这题是要我们删点,既然是删点,那么就要拆点,容量就是1. 接下来凡是能联系的,就连边,容量为INF,因为我们不是要删除这些边.跑遍最大流就能算出至少要删除多少个点. 这道题的关键是要字典序顺序输出最小割…

POJ 3281 Dining (网络流) Description Cows are such finicky eaters. Each cow has a preference for certain foods and drinks, and she will consume no others. Farmer John has cooked fabulous meals for his cows, but he forgot to check his menu against their…

POJ 2431 Expedition(探险) Time Limit: 1000MS   Memory Limit: 65536K [Description] [题目描述] A group of cows grabbed a truck and ventured on an expedition deep into the jungle. Being rather poor drivers, the cows unfortunately managed to run over a rock an…

POJ 3414 Pots(罐子) Time Limit: 1000MS    Memory Limit: 65536K Description - 题目描述 You are given two pots, having the volume of A and B liters respectively. The following operations can be performed: FILL(i)        fill the pot i (1 ≤ i ≤ 2) from the ta…

POJ 1847 Tram (最短路径) Description Tram network in Zagreb consists of a number of intersections and rails connecting some of them. In every intersection there is a switch pointing to the one of the rails going out of the intersection. When the tram ent…