首先比较容易想到是状态压缩DP 令$f[S]$表示选取了集合$S$以后,已经送了最少次数$cnt$且当前电梯剩下的体积$rest$最大(即$f[S]$是一个二元组$(cnt, rest)$) 于是$f[S] = min_{i \in S} f[S - {i}] + v[i]$ 重载的$<$和$+$运算详情就请看程序好了,反正就是一个贪心思想,总复杂度$O(n * 2 ^ {n - 1})$ /****************************************************…

第一眼是3^n*n的做法...然而并不可行T T 后来发现对于奶牛的一个状态i,最优情况下剩下那个可以装奶牛的电梯剩下的可用重量是一定的,于是我们设f[i]表示奶牛状态为i的最小电梯数,g[i]为奶牛状态为i剩下那个电梯的可用重量,每次都枚举一个奶牛看看能不能塞进电梯就好,塞不进就新开一个电梯. #include<iostream> #include<cstring> #include<cstdlib> #include<cstdio> #include&l…

  2621: [Usaco2012 Mar]Cows in a Skyscraper Time Limit: 20 Sec  Memory Limit: 128 MBSubmit: 303  Solved: 150[Submit][Status][Discuss] Description [Mark Gordon, Neal Wu, Fatih Gelgi, 2012] A little known fact about Bessie and friends is that they love…

2620: [Usaco2012 Mar]Haybale Restacking Time Limit: 5 Sec  Memory Limit: 128 MBSubmit: 201  Solved: 111[Submit][Status][Discuss] Description Farmer John has just ordered a large number of bales of hay. He would like to organize these into N piles (1…

洛谷题目链接:[USACO12MAR]摩天大楼里的奶牛Cows in a Skyscraper 题目描述 A little known fact about Bessie and friends is that they love stair climbing races. A better known fact is that cows really don't like going down stairs. So after the cows finish racing to the top…

P3052 [USACO12MAR]摩天大楼里的奶牛Cows in a Skyscraper 题目描述 A little known fact about Bessie and friends is that they love stair climbing races. A better known fact is that cows really don't like going down stairs. So after the cows finish racing to the top…

题目链接 状压\(dp\) 根据套路,先设\(f[sta]\)为状态为\(sta\)时所用的最小分组数. 可以发现,这个状态不好转移,无法判断是否可以装下新的一个物品.于是再设一个状态\(g[sta]\)表示状态为\(sta\)时 每组剩下的体积的最大值 的最大值,当枚举状态为\(sta\),枚举到第\(i\)个时,可以得到\(g\)的转移: \[ g[v]=max(g[v],g[sta]-w[i]) \] 其中,\(v​\)为转移后的状态. 然后每次就可以根据\(g\)来转移\(f\)了. #…

题目描述 A little known fact about Bessie and friends is that they love stair climbing races. A better known fact is that cows really don't like going down stairs. So after the cows finish racing to the top of their favorite skyscraper, they had a proble…

题目描述 A little known fact about Bessie and friends is that they love stair climbing races. A better known fact is that cows really don't like going down stairs. So after the cows finish racing to the top of their favorite skyscraper, they had a proble…

这个状压dp其实很明显,n < 18写在前面了当然是状压.状态其实也很好想,但是有点问题,就是如何判断空间是否够大. 再单开一个g数组,存剩余空间就行了. 题干: 题目描述 A little known fact about Bessie and friends is that they love stair climbing races. A better known fact is that cows really don't like going down stairs. So after…