题意:有N家家店,每家店都对K种货物有需求:同时有M家仓库,对K钟货物有供应.对于每种货物,每个仓库送至每家店都有自己的单位费用.求满足所有店所有货物的最小费用 分析:对于每一种货物,如果总需求大于总费用,那么无解的:否则可以用KM匹配求解每一种货物的最小费用. 因为KM求的是最优匹配,所以建图的时候,建负权边即可. 将每一份需求和每一份供应都离散化,而不是把一个店的需求和每个一仓库的供应建立边. #include<stdio.h> #include<cstring> #inclu…

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: Poj  2516  Minimum Cost 题目描述: 有n个商店,m个仓储,每个商店和仓库都有k种货物.嘛!现在n个商店要开始向m个仓库发出订单了,订单信息为当前商店对每种货物的需求量.不同的商店从不同的仓库购买不同货物花费不同,问是不是能满足所有商店的要求,如果能商店花费总和最小为多少? 解题思路: 简单的费用流,要跑K次最小花费最大流,每次只对一种货物建图跑费用流.每次建图以0为源点, [1,m]为仓库, [m+1, n+m]为商店, n+m+1为汇点.0与[1,m]连边,…

POJ 2516 Minimum Cost 链接:http://poj.org/problem?id=2516 题意:有M个仓库.N个商人.K种物品.先输入N,M.K.然后输入N行K个数,每一行代表一个商人要购买的物品,当中K个数分别表示要购买的每件商品数. 然后是M行K个数,每行表示仓库里的情况,当中K个数分别每种物品的库存量. 接下来是K个矩阵,每一个矩阵为N*M,分别表示第K种物品从M个仓库运到第N个商人的花费.问是否能合理安排,使得花费最少.假设不行就输出-1. 思路: 一開始的时候.居…

传送门:poj.org/problem?id=2516 题意: 有m个仓库,n个买家,k个商品,每个仓库运送不同商品到不同买家的路费是不同的.问为了满足不同买家的订单的最小的花费. 思路: 设立一个源点S和汇点T,从源点S到每个仓库(1-m)连上容量为商品A的库存.费用为0的边,每个仓库再向每个不同的买家连上容量inf,费用为路费的边.每个顾客向汇点连一条容量为自己对商品A的需求个数.费用为0的边.跑一边费用流即可.这只有运送一个商品的费用,对,那我们就对不同商品建不同的图,一共跑K边,累计答案…

题面 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 (marked from 1 to M), each provides K different k…

Minimum Cost Time Limit: 4000MS   Memory Limit: 65536K Total Submissions: 13511   Accepted: 4628 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)…

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 (marked from 1 to M), each provides K di…

题目链接:http://poj.org/problem?id=2516 题目大意: 第一行是N,M,K 接下来N行:第i行有K个数字表示第i个卖场对K种商品的需求情况 接下来M行:第j行有K个数字表示第j个库房对K种商品的存货情况 接下来K个N*M的矩阵: 每个矩阵(i,j)表示第k种商品从第j个库房运到第i个卖场的运费(单价) 求满足所有需求的最小花费,如果不能全部满足输出-1. 解题思路: 拆点,对于第k种商品有: 把每个卖场的需求按件数拆成各个小点(比如需要x件就看做x个点) 把每个库房的…

题意略: 思路: 这题比较坑的地方是把每种货物单独建图分开算就ok了. #include<stdio.h> #include<queue> #define MAXN 500 #define MAXM 10002*4 #define INF 10000000 using namespace std; //起点编号必须最小,终点编号必须最大 bool vis[MAXN]; //spfa中记录是否在队列里边 ][]; int max_flow; struct point{ int x,y…

题目: 给出n*kk的矩阵,格子a[i][k]表示第i个客户需要第k种货物a[i][k]单位. 给出m*kk的矩阵,格子b[j][k]表示第j个供应商可以提供第k种货物b[j][k]单位. 再给出k个n*m的矩阵,格子c[k][i][j]表示第k种货物由j供应商提供给客户i的话,每单位运费为c[k][i][j]. 问最小费用. 分析: 刚开始时,虽然考虑到每种货物其实是不相关的,但是想到在跑费用流时应该没多大影响,所以直接建图,跑最小费用流,TLE了... 后来对于每种货物单独来考虑,即建图之后…

每个物品分开做最小费用最大流. #include<cstdio> #include<cstring> #include<cmath> #include<vector> #include<queue> #include<algorithm> using namespace std; +; const int INF=0x7FFFFFFF; struct Edge { int from,to,cap,flow,cost; }; int n…

1.K种物品,M个供应商,N个收购商.每种物品从一个供应商运送到一个收购商有一个单位运费.每个收购商都需要K种物品中的若干.求满足所有收购商需求的前提下的最小运费. 2.K种物品拆开来,分别对每种物品进行最小费用最大流计算. 建立超级源点和超级汇点:超级源点流向M个供应商,容量为供应商的存储量,费用为0:N个收购商流向超级源点,容量为收购商的需求量,费用为0. 另外,供应商流向收购商,容量为无穷大,费用为对应的单位运费. 3. 1.Bellman-Ford: #include<iostream>…

题意:对一个带权有向图,将所有点纳入一个或多个环中,且每个点只出现一次,求其所有环的路径之和最小值. 分析:每个点都只出现一次,那么换个思路想,每个点入度出度都为1.将一个点拆成两个点,一个作为入度点,一个作为出度点.每个入度点都和一个出度点匹配,且不为自己.那么可以将问题转化为二分图最优匹配的问题,这里我们求得是最短路径,那么建图时,把权值取反.这样最优匹配后取反就是最短的路径. #include <cstdio> #include <vector> #include <a…

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 (marked from 1 to M), each provides K di…

就是最基本的二分图最优匹配,将每个人向每个房子建一条边,权值就是他们manhattan距离.然后对所有权值取反,求一次最大二分图最优匹配,在将结果取反就行了. #include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #define Maxn 110 using namespace std; int n;//点的数目 int lx[Maxn],ly[Maxn]; //顶…

/** 题目:hdu2255 奔小康赚大钱 km算法 链接:http://acm.hdu.edu.cn/showproblem.php?pid=2255 题意:lv 思路:最优匹配(最大权完美匹配) km算法 模板来自:http://www.cnblogs.com/wenruo/p/5264235.html 如果是求最小权完美匹配,那么将所有权值取相反数,然后求得最大权,输出最大权的相反数即可. */ #include <iostream> #include <cstring> #…

题目大意:求二分图的最优匹配(首先数目最大, 其次权值最大). 解题关键:KM算法 复杂度:$O(n^3)$ #include<cstdio> #include<cstring> #include<algorithm> #include<cstdlib> #include<iostream> #include<cmath> using namespace std; typedef long long ll; ; const int i…

Minimum Cost http://poj.org/problem?id=2516 Time Limit: 4000MS   Memory Limit: 65536K Total Submissions: 19019   Accepted: 6716 Description Dearboy, a goods victualer, now comes to a big problem, and he needs your help. In his sale area there are N s…

装盒子   基准时间限制:1 秒 空间限制:131072 KB 分值: 160 有n个长方形盒子,第i个长度为Li,宽度为Wi,我们需要把他们套放.注意一个盒子只可以套入长和宽分别不小于它的盒子,并且一个盒子里最多只能直接装入另外一个盒子 (但是可以不断嵌套),例如1 * 1 可以套入2 * 1,而2 * 1再套入2 * 2.套入之后盒子占地面积是最外面盒子的占地面积.给定N个盒子大小,求最终最小的总占地面积. Input 第一行一个数N表示盒子的个数. 接下来N行,每行两个正整数,表示每个盒子…

Minimum Cost Time Limit: 4000MS   Memory Limit: 65536K Total Submissions: 19088   Accepted: 6740 题目链接:http://poj.org/problem?id=2516 Description: Dearboy, a goods victualer, now comes to a big problem, and he needs your help. In his sale area there a…

http://poj.org/problem?id=2195 对km算法不理解,模板用的也不好. 下面是大神的解释. KM算法的要点是在相等子图中寻找完备匹配,其正确性的基石是:任何一个匹配的权值之和都不大于所有顶点的顶标之和,而能够取到相等的必然是最大权匹配. 左右两边点数不等时,KM算法的正确性也是可以得到保证的.原因如下: 由KM算法中可行点标的定义,有: 任意匹配的权值 <= 该匹配所覆盖的所有点的顶标值 <= KM算法所得到的匹配所覆盖的所有点的顶标值 = KM算法所得到的的匹配的权…

[POJ2516]Minimum Cost 题意:有N个收购商.M个供应商.K种物品.对于每种物品,每个供应商的供应量和每个收购商的需求量已知.每个供应商与每个收购商之间运送该物品的运费已知.求满足收购商要求的前提下的最小运费.(n,M,K<=50,每种物品供求量<=3,单位运费<=100) 题解:怎么看怎么是最小费用流,但是刚学的KM算法,还是要用一下的~ 由于各种物品间没有影响,所以可以将k种物品拆开:由于供求量≤3,所以可以将供应商和收购商都拆开,然后跑KM算法. #include…

题目链接:https://www.nowcoder.com/acm/contest/145/A A.Minimum Cost Perfect Matching You have a complete bipartite graph where each part contains exactly n nodes, numbered from 0 to n - 1 inclusive.The weight of the edge connecting two vertices with numbe…

题目链接:https://vjudge.net/problem/POJ-2516 Minimum Cost Time Limit: 4000MS   Memory Limit: 65536K Total Submissions: 17650   Accepted: 6205 Description Dearboy, a goods victualer, now comes to a big problem, and he needs your help. In his sale area the…

Minimum Cost Time Limit: 4000MS   Memory Limit: 65536K Total Submissions: 19883   Accepted: 7055 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)…

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 (marked from 1 to M), each provides K di…

There are N piles of stones arranged in a row.  The i-th pile has stones[i] stones. A move consists of merging exactly K consecutive piles into one pile, and the cost of this move is equal to the total number of stones in these K piles. Find the mini…

There are N piles of stones arranged in a row.  The i-th pile has stones[i] stones. A move consists of merging exactly K consecutive piles into one pile, and the cost of this move is equal to the total number of stones in these K piles. Find the mini…

There are N piles of stones arranged in a row.  The i-th pile has stones[i] stones. A move consists of merging exactly K consecutive piles into one pile, and the cost of this move is equal to the total number of stones in these K piles. Find the mini…