Cleaning Shifts Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 4422   Accepted: 1482 Description Farmer John's cows, pampered since birth, have reached new heights of fastidiousness. They now require their barn to be immaculate. Farmer…

https://vjudge.net/problem/POJ-3171.(有价值的区间全覆盖问题) (lyd例题)朴素DP很好想,$f[i]$表示将右端点从小到大排序后从$L$(要求覆盖的大区间)到第$i$个区间的右端点都覆盖完成时最小化费.无解则为INF.然后利用排序.右端点单调性,每次枚举前面dp过的右端点落在现在左端点及其右侧(或相邻)的,去最小dp值加上现在费用.然后$O(n^2)$就可以水过啦..因为常数特别小,数据也才1e4嘛..优化的话因为每次查的都是一段区间里的右端点最值,所以线…

题目:http://poj.org/problem?id=3171 题意:给你n个区间[a,b],每个区间都有一个费用c,要你用最小的费用覆盖区间[M,E] 分析:经典的区间覆盖问题,百度可以搜到这个专题. 线段覆盖问题一般考虑贪心和DP,但是每个区间又有了一个费用c,本渣觉得贪心貌似不太行(不知道神犇门有木有贪心解法),然后便考虑DP 设f[i]表示覆盖[M,i]的最小总费用 那么有f[t[i].a]=min(f[j]+t[i].c) t[i].a-1<=j<=t[i].b-1 那么ans=…

传送门 题目大意 有一个大区间和n个小区间,每个小区间都有一个代价,求最少付出多少代价可以使得小区间完全覆盖大区间. 分析为了方便起见我们先将s变为2,其它的位置都对应更改以便后期处理.我们考虑以t1为第一关键字,t2为第二关键字将所有奶牛排序.用dp[i][j]表示考虑到第i只牛,覆盖到点j最少需要多少钱.我们可以将i这一维去掉,则dp[j]=min{dp[j],dp[j'](t1-1<=j'<=t2-1)}.然后进行线段树优化就可以了. 代码 #include<iostream>…

题目大意.N个区间覆盖[T1,T2]及相应的代价S,求从区间M到E的所有覆盖的最小代价是多少. (1 <= N <= 10,000).(0 <= M <= E <= 86,399). 思路是DP,首先将每一个区间依照T2从小到大排序,设dp(k)为从m覆盖到k所需最小代价,则有 dp(T2[i]) = min(dp(T2[i]), {dp(j) + Si,  T1[i] - 1<=j <= T2[i]}),对于 {dp(j) + Si,  T1[i] - 1<…

题意 POJ2376 Cleaning Shifts 0x50「动态规划」例题 http://bailian.openjudge.cn/practice/2376 总时间限制: 1000ms 内存限制: 65536kB 描述 Farmer John is assigning some of his N (1 <= N <= 25,000) cows to do some cleaning chores around the barn. He always wants to have one c…

Cleaning Shifts Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 32561   Accepted: 7972 Description Farmer John is assigning some of his N (1 <= N <= 25,000) cows to do some cleaning chores around the barn. He always wants to have one co…

[BZOJ1672][Usaco2005 Dec]Cleaning Shifts Description Farmer John's cows, pampered since birth, have reached new heights of fastidiousness. They now require their barn to be immaculate. Farmer John, the most obliging of farmers, has no choice but hire…

http://poj.org/problem?id=2376 Cleaning Shifts Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 12604   Accepted: 3263 Description Farmer John is assigning some of his N (1 <= N <= 25,000) cows to do some cleaning chores around the barn.…

POJ 2376 Cleaning Shifts(轮班打扫) Time Limit: 1000MS   Memory Limit: 65536K [Description] [题目描述] Farmer John is assigning some of his N (1 <= N <= 25,000) cows to do some cleaning chores around the barn. He always wants to have one cow working on clean…

Cleaning Shifts 题目连接: http://poj.org/problem?id=2376 Description Farmer John is assigning some of his N (1 <= N <= 25,000) cows to do some cleaning chores around the barn. He always wants to have one cow working on cleaning things up and has divided…

3389: [Usaco2004 Dec]Cleaning Shifts安排值班 Time Limit: 1 Sec  Memory Limit: 128 MBSubmit: 218  Solved: 86[Submit][Status][Discuss] Description     一天有T(1≤T≤10^6)个时段．约翰正打算安排他的N(1≤N≤25000)只奶牛来值班,打扫 打扫牛棚卫生．每只奶牛都有自己的空闲时间段[Si,Ei](1≤Si≤Ei≤T),只能把空闲的奶牛安排出来值班．而…

Cleaning Shifts Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 2743   Accepted: 955 Description Farmer John's cows, pampered since birth, have reached new heights of fastidiousness. They now require their barn to be immaculate. Farmer J…

3389: [Usaco2004 Dec]Cleaning Shifts安排值班 Time Limit: 1 Sec  Memory Limit: 128 MBSubmit: 45  Solved: 26[Submit][Status] Description     一天有T(1≤T≤10^6)个时段．约翰正打算安排他的N(1≤N≤25000)只奶牛来值班,打扫 打扫牛棚卫生．每只奶牛都有自己的空闲时间段[Si,Ei](1≤Si≤Ei≤T),只能把空闲的奶牛安排出来值班．而且,每个时间段必需有…

1672: [Usaco2005 Dec]Cleaning Shifts 清理牛棚 Time Limit: 5 Sec  Memory Limit: 64 MBSubmit: 414  Solved: 191[Submit][Status] Description Farmer John's cows, pampered since birth, have reached new heights of fastidiousness. They now require their barn to…

Cleaning Shifts Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 15143   Accepted: 3875 Description Farmer John is assigning some of his N (1 <= N <= 25,000) cows to do some cleaning chores around the barn. He always wants to have one co…

题目 3389: [Usaco2004 Dec]Cleaning Shifts安排值班 Time Limit: 1 Sec  Memory Limit: 128 MB Description     一天有T(1≤T≤10^6)个时段．约翰正打算安排他的N(1≤N≤25000)只奶牛来值班,打扫 打扫牛棚卫生．每只奶牛都有自己的空闲时间段[Si,Ei](1≤Si≤Ei≤T),只能把空闲的奶牛安排出来值班．而且,每个时间段必需有奶牛在值班．  那么,最少需要动用多少奶牛参与值班呢?如果没有办法安排…

题目 1672: [Usaco2005 Dec]Cleaning Shifts 清理牛棚 Time Limit: 5 Sec  Memory Limit: 64 MB Description Farmer John's cows, pampered since birth, have reached new heights of fastidiousness. They now require their barn to be immaculate. Farmer John, the most…

题目地址: http://poj.org/problem?id=2376 题目内容: Cleaning Shifts Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 12226   Accepted: 3187 Description Farmer John is assigning some of his N (1 <= N <= 25,000) cows to do some cleaning chores arou…

3389: [Usaco2004 Dec]Cleaning Shifts安排值班 Time Limit: 1 Sec  Memory Limit: 128 MBSubmit: 102  Solved: 46[Submit][Status][Discuss] Description     一天有T(1≤T≤10^6)个时段．约翰正打算安排他的N(1≤N≤25000)只奶牛来值班,打扫 打扫牛棚卫生．每只奶牛都有自己的空闲时间段[Si,Ei](1≤Si≤Ei≤T),只能把空闲的奶牛安排出来值班．而…

BZOJ_1672_[Usaco2005 Dec]Cleaning Shifts 清理牛棚_动态规划+线段树 题意:  约翰的奶牛们从小娇生惯养,她们无法容忍牛棚里的任何脏东西．约翰发现,如果要使这群有洁癖的奶牛满意,他不得不雇佣她们中的一些来清扫牛棚, 约翰的奶牛中有N(1≤N≤10000)头愿意通过清扫牛棚来挣一些零花钱．由于在某个时段中奶牛们会在牛棚里随时随地地乱扔垃圾,自然地,她们要求在这段时间里,无论什么时候至少要有一头奶牛正在打扫．需要打扫的时段从某一天的第M秒开始,到第E秒结束f0…

P4644 [Usaco2005 Dec]Cleaning Shifts 清理牛棚 你有一段区间需要被覆盖(长度 <= 86,399) 现有 \(n \leq 10000\) 段小线段, 每段可以从 \(l_{i}\) 到 \(r_{i}\) 花费为 \(s_{i}\) 求覆盖整个区间的最小花费 错误日志: 初始化时应该是 \(dp[L - 1]\) 为 \(0\) 而不是 \(dp[1]\) 为 \(0\) , 因为只需要覆盖 \([L, R]\) Solution 设 \(dp[n]\) 表…

3389: [Usaco2004 Dec]Cleaning Shifts安排值班 Time Limit: 1 Sec  Memory Limit: 128 MB Description     一天有T(1≤T≤10^6)个时段．约翰正打算安排他的N(1≤N≤25000)只奶牛来值班,打扫 打扫牛棚卫生．每只奶牛都有自己的空闲时间段[Si,Ei](1≤Si≤Ei≤T),只能把空闲的奶牛安排出来值班．而且,每个时间段必需有奶牛在值班．  那么,最少需要动用多少奶牛参与值班呢?如果没有办法安排出合理…

[Usaco2005 Dec] Cleaning Shifts 清理牛棚 题目描述 Farmer John's cows, pampered since birth, have reached new heights of fastidiousness. They now require their barn to be immaculate. Farmer John, the most obliging of farmers, has no choice but hire some of th…

Cleaning Shifts Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 31194   Accepted: 7677 Description Farmer John is assigning some of his N (1 <= N <= 25,000) cows to do some cleaning chores around the barn. He always wants to have one co…

Cleaning Shifts Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 11542   Accepted: 3004 Description Farmer John is assigning some of his N (1 <= N <= 25,000) cows to do some cleaning chores around the barn. He always wants to have one co…

Cleaning Shifts Farmer John is assigning some of his N (1 <= N <= 25,000) cows to do some cleaning chores around the barn. He always wants to have one cow working on cleaning things up and has divided the day into T shifts (1 <= T <= 1,000,000…

Cleaning Shifts Descriptions: 原文是English,我这就直接上Chinese了,想看原文的点一下链接哦 大表哥分配 N (1 <= N <= 25,000) 只中的一些奶牛在牛棚附近做些清洁. 他总是要让至少一只牛做清洁.他把一天分成T段(1 <= T <= 1,000,000), 第一段是1,最后一段是T 每只奶牛只在一些时间段有空.奶牛如果选择某一段时间,则必须完成整段时间的工作 你的任务是帮助FJ安排一些奶牛,使每段时间至少有一只奶牛被安排来做…

Cleaning Shifts bzoj-3389 Usaco-2004Dec 题目大意:每天有n个时间段,每个时间段都必须安排一个奶牛值班.有m个奶牛,每个奶牛只有一个空闲时间s[i]~e[i],求至少动用多少奶牛. 注释:$1\le n\le 10^6$,$1\le m\le 25,000$. 想法:神题 我们将所有的时间点排成一排,然后对每一个i+1向i连一条无代价的边. 对于每一个s[i]向其对应的e[i]连边,代价为1. 然后求1到n的最短路即可 这样建图的道理:首先,从后面的时间点向…

<pre name="code" class="html"> Cleaning Shifts Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 14425   Accepted: 3700 Description Farmer John is assigning some of his N (1 <= N <= 25,000) cows to do some cleani…