<题目链接> 题目大意: 有N头牛,F种食物,D种饮料,每一头牛都有自己喜欢的食物和饮料,且每一种食物和饮料都只有一份,让你分配这些食物和饮料,问最多能使多少头牛同时获得自己喜欢的食物和饮料. 解题分析: 开始还以为是一道匹配问题,后面才知道这是用网络流求解. 首先我们要明确,如果按照源点——>食物——>牛——>饮料——>汇点这样建图,是不符合题目条件的.因为题目要求每头牛只能吃一份食物和饮料,而这样建图,如果一头牛对应多个食物和饮料,那这样那头牛是可以吃多份食物和饮料…

题目链接 题意 有\(N\)头牛,\(F\)个食物和\(D\)个饮料.每头牛都有自己偏好的食物和饮料列表. 问该如何分配食物和饮料,使得尽量多的牛能够既获得自己喜欢的食物又获得自己喜欢的饮料. 建图 在 源点 到 食物 之间加边,边权为\(1\) 在 饮料 到 汇点 之间加边,边权为\(1\) 将牛拆成两点,在两点之间加边,边权为\(1\) 这一点很重要,可以从以下两个方面去考虑: 1) 从含义上,只要流为1,这头牛就被满足了,多了就纯属是浪费. 2) 从操作上,最后答案是根据最大流的值来判断的…

Dining Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 20052   Accepted: 8915 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 fabulo…

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 3281 Dining id=3281" target="_blank" style="">题目链接 题意:n个牛.每一个牛有一些喜欢的食物和饮料.每种食物饮料仅仅有一个.问最大能匹配上多少仅仅牛每一个牛都能吃上喜欢的食物和喜欢的饮料 思路:最大流.建模源点到每一个食物连一条边,容量为1,每一个饮料向汇点连一条边容量为1,然后因为每一个牛有容量1.所以把牛进行拆点.然后食物连向牛的入点,牛的出点连向食物,跑一下最大流就可以 代码: #incl…

POJ 2135 Farm Tour (网络流,最小费用最大流) Description When FJ's friends visit him on the farm, he likes to show them around. His farm comprises N (1 <= N <= 1000) fields numbered 1..N, the first of which contains his house and the Nth of which contains the b…

POJ 2516 Minimum Cost (网络流,最小费用流) Description Dearboy, a goods victualer, now comes to a big problem, and he needs your help. In his sale area there are N shopkeepers (marked from 1 to N) which stocks goods from him.Dearboy has M supply places (marke…

[题目链接] http://poj.org/problem?id=3281 [题目大意] 给出一些食物,一些饮料,每头牛只喜欢一些种类的食物和饮料, 但是每头牛最多只能得到一种饮料和食物,问可以最多满足几头牛的要求 即同时得到喜欢的饮料和食物 [题解] 建立一个源点连接食物,汇点连接饮料,中间连接牛, 为了防止同一头牛占用多个资源,所以我们对牛进行拆点,限流为1. [代码(Isap)] #include <cstdio> #include <cstring> using names…

Dining Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 18230   Accepted: 8132 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 fabulo…

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 preferences. Although…