Golden Eggs Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 304    Accepted Submission(s): 172 Problem Description There is a grid with N rows and M columns. In each cell you can choose to put a…

Golden Eggs Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 501    Accepted Submission(s): 281 Problem Description There is a grid with N rows and M columns. In each cell you can choose to put…

http://acm.hdu.edu.cn/showproblem.php?pid=3820 题意:n*m的格子,每个格子放金蛋或银蛋,每个格子的金蛋和银蛋都有一个对应的点权,如果有两个金蛋相连,则需要G的代价,如果有两个银蛋相连,需要S的代价. 思路: 这道题和HDU的格子取数是一个套路. 在前面的格子取数问题中,我们奇偶建图,相邻点之间连INF就代表这两个点中至少会选择一个,由于是最小割,肯定是选择权值小的点.这道题目的建图稍微复杂点,因为每个格子有三种选择,即可以选择放金蛋或是放银蛋或空着…

题目大概说给一个n*m的格子,每个格子放金蛋或银蛋都会得到不同的价值,当然也可以不放,不过如果存在相邻的两个格子都是金蛋会损失价值g,都是银则损失s.问能得到的最大价值. 有点像二者选一的最小割模型,所以应该能想到用最小割求解,最小割的目的就是最小化损失的价值,包括不放金蛋或不放银蛋以及相邻相同蛋的损失的价值: 对格子黑白染色形成x和y两部分的点,并拆成两点x.x'和y.y' 源点向x连容量为该格子放金蛋的价值的边,x'向汇点连容量为该格子放银蛋的价值的边 源点向y连容量为该格子放银蛋的价值的边…

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HDU 5877 Weak Pair(弱点对) Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 262144/262144 K (Java/Others) Description 题目描述 You are given a rooted tree of N nodes, labeled from 1 to N. To the ith node a non-negative value ai is assigned. An ordere…

HDU 5813 Elegant Construction(优雅建造) Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Description 题目描述 Being an ACMer requires knowledge in many fields, because problems in this contest may use physics, biology, and…

HDU 5818 Joint Stacks(联合栈) Time Limit: 8000/4000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Description 题目描述 A stack is a data structure in which all insertions and deletions of entries are made at one end, called the "top" of…

HDU 2222 Keywords Search(查询关键字) Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 131072/131072 K (Java/Others) [Description] [题目描述] In the modern time, Search engine came into the life of everybody like Google, Baidu, etc. Wiskey also wants to br…

HDU 3549 Flow Problem(最大流) Time Limit: 5000/5000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others) [Description] [题目描述] Network flow is a well-known difficult problem for ACMers. Given a graph, your task is to find out the maximum flow for t…