这两道题目都是多重二分匹配+枚举的做法,或者可以用网络流,实际上二分匹配也就实质是网络流,通过枚举区间,然后建立相应的图,判断该区间是否符合要求,并进一步缩小范围,直到求出解.不同之处在对是否满足条件的判断,可以求最大流或者最大匹配看匹配数目是否满足题意. POJ 2289: 多重二分匹配:360ms #include <iostream> #include <cstdio> #include <climits> #include <cstring> #in…

POJ 2289 Jamie's Contact Groups / UVA 1345 Jamie's Contact Groups / ZOJ 2399 Jamie's Contact Groups / HDU 1699 Jamie's Contact Groups / SCU 1996 Jamie's Contact Groups (二分,二分图匹配) Description Jamie is a very popular girl and has quite a lot of friends…

题目链接: Poj 2289 Jamie's Contact Groups 题目描述: 给出n个人的名单和每个人可以被分到的组,问将n个人分到m个组内,并且人数最多的组人数要尽量少,问人数最多的组有多少人? 解题思路: 二分图多重匹配相对于二分匹配来说不再是节点间的一一对应,而是Xi可以对应多个Yi.所以我们就需要一个限制(Xi最多匹配几个Yi).当Yi需要匹配Xi的时候,Xi的匹配未到上限,直接匹配,否则进行增广路.其实是二分图多重匹配的模板题,再套一个二分枚举最多组的人数就OK咯.下面就上板…

题目链接:http://poj.org/problem?id=2289 Jamie's Contact Groups Time Limit: 7000MS   Memory Limit: 65536K Total Submissions: 8473   Accepted: 2875 Description Jamie is a very popular girl and has quite a lot of friends, so she always keeps a very long con…

Jamie's Contact Groups Time Limit:7000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Submit Status Practice POJ 2289 Description Jamie is a very popular girl and has quite a lot of friends, so she always keeps a very long contact list…

Jamie's Contact Groups Time Limit: 7000MS   Memory Limit: 65536K Total Submissions: 6511   Accepted: 2087 Description Jamie is a very popular girl and has quite a lot of friends, so she always keeps a very long contact list in her cell phone. The con…

题目大意: 有n个人,可以分成m个组,现在给出你每个人可以去的组的编号,求分成的m组中人数最多的组最少可以有多少人. 算法讨论: 首先喷一下这题的输入,太恶心了. 然后说算法:最多的最少,二分的字眼.二分什么,因为我们说的是组的人,所以要对组的流出量进行二分.其余的都连流量为1的边,然后对“小组”点的流出量二分连边,最后跑最大流判断 是否等于N即可.还是蛮简单的. Codes: #include <cstdio> #include <cstring> #include <cs…

Description Jamie is a very popular girl and has quite a lot of friends, so she always keeps a very long contact list in her cell phone. The contact list has become so long that it often takes a long time for her to browse through the whole list to f…

题意: Jamie有很多联系人,但是很不方便管理,他想把这些联系人分成组,已知这些联系人可以被分到哪个组中去,而且要求每个组的联系人上限最小,即有一整数k,使每个组的联系人数都不大于k,问这个k最小是多少? 题目分析: 多重匹配,二分枚举所有极限值. 多重匹配如何匹配? 假如我们有两个集合X, Y 但是呢 Y可以匹配多个X, 这个时候我们需要给这个匹配设置一个极限值.比如Y可以匹配三个X. 假如匹配的值不到三个X我们就将他们匹配, 直到到达极限值为止.在这里Y要保存所有的与之匹配的X,若是匹配值…

二分答案+网络最大流 #include<cstdio> #include<cstring> #include<cmath> #include<vector> #include<queue> #include<algorithm> using namespace std; int N,M; + ; const int INF = 0x7FFFFFFF; struct Edge { int from, to, cap, flow; Edg…