CF666B. World Tour 题意: 给定一张边权为 1 的有向图,求四个不同点 A, B, C, D 使得 dis(A, B) + dis(B, C) + dis(C, D) 取最大值,dis表示最短路距离 1 ≤ n ≤ 3000, 1 ≤ m ≤ 5000 我又写了假做法呜呜呜 首先当然\(O(nm)\)预处理两点之间最短路 然后预处理出从每个点开始前3个dis最大的点 假做法: 贪心,枚举A,贪心选择dis较大的BCD,就是3*3*3搜索选出B.C.D 假的原因: 贪心不成立,因…

题意:给你一张有向图,叫你给出四个点的序列a,b,c,d,使得这四个点依次间的最短路之和最大.(4 ≤ n ≤ 3000, 3 ≤ m ≤ 5000) 思路:O(n4)可用来对拍 我们需要O(n2)级别的算法 若枚举c,d,预处理出x到b比较远的3个x,d到y比较远的3个y,时间复杂度O(9n2) 为什么是3个而不是2个? abc已枚举,若d的备选是ab就要GG,所以应该多一个备用,也就是三个点 ..,..,..]of longint; head,vet,next,b,flag,q,x,y:..…

Sightseeing tour Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 9276   Accepted: 3924 Description The city executive board in Lund wants to construct a sightseeing tour by bus in Lund, so that tourists can see every corner of the beauti…

Euler Tour Tree最大的优点就是可以方便的维护子树信息,这点LCT是做不到的.为什么要维护子树信息呢..?我们可以用来做fully dynamic connectivity(online). Euler Tour Tree 维护将树中的边u--v变成u->v,v->u后的Euler Tour. 换根: 因为Euler Tour是一个环,那么我们可以在任意一个k->u的地方切断,然后把这段东西接到最后去,这样就把u变成根了 Link: 先换根,然后添加u->v与v->…

Tour Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 4307   Accepted: 1894 Description John Doe, a skilled pilot, enjoys traveling. While on vacation, he rents a small plane and starts visiting beautiful places. To save money, John must…

题目描述: 1015. Jill's Tour Paths Constraints Time Limit: 1 secs, Memory Limit: 32 MB Description Every year, Jill takes a bicycle tour between two villages. There are different routes she can take between these villages, but she does have an upper limit…

Sightseeing tour Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 8859   Accepted: 3728 Description The city executive board in Lund wants to construct a sightseeing tour by bus in Lund, so that tourists can see every corner of the beauti…

A quick tour of JSON libraries in Scala Update (18.11.2015): added spray-json-shapeless libraryUpdate (06.11.15): added circe library Some time ago I wrote a post on relational database access in Scala since I was looking for a library and there were…

Sightseeing tour Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 6986   Accepted: 2901 Description The city executive board in Lund wants to construct a sightseeing tour by bus in Lund, so that tourists can see every corner of the beauti…

Sightseeing tour   Description The city executive board in Lund wants to construct a sightseeing tour by bus in Lund, so that tourists can see every corner of the beautiful city. They want to construct the tour so that every street in the city is vis…

  Farm Tour Time Limit: 2MS   Memory Limit: 65536KB   64bit IO Format: %I64d & %I64u Description When FJ's friends visit him on the farm, he likes to show them around. His farm comprises N (1 <= N <= 1000) fields numbered 1..N, the first of whic…

Tour Time Limit: 3000MS   Memory Limit: Unknown   64bit IO Format: %lld & %llu Description   John Doe, a skilled pilot, enjoys traveling. While on vacation, he rents a small plane and starts visiting beautiful places. To save money, John must determi…

Tour Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 3929   Accepted: 1761 Description John Doe, a skilled pilot, enjoys traveling. While on vacation, he rents a small plane and starts visiting beautiful places. To save money, John must…

http://www.spoj.com/problems/FTOUR2/ 先前看了一会题解就自己yy出来了...对拍过后交tle.................. 自己造了下大数据........tle......................... what? 首先来看经过当前点的路径: 设g[x,i]表示第x个孩子能得到的路径上黑点最多有i个(注意是最多)的最大长度,因为遍历的节点最坏为n个(第一层),因此在每一层都是$O(n)$的,可以承受. 考虑转移答案 $$ans[x]=max\{…

Sightseeing tour Time Limit: 1000MS Memory Limit: 10000K Total Submissions: 8276 Accepted: 3489 Description The city executive board in Lund wants to construct a sightseeing tour by bus in Lund, so that tourists can see every corner of the beautiful…

                                                            Sightseeing tour Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 9100   Accepted: 3830 Description The city executive board in Lund wants to construct a sightseeing tour by bus…

1307: City Tour Time Limit: 1 Sec  Memory Limit: 128 MB [Submit][Status][Web Board] Description Alice想要从城市A出发到城市B,由于Alice最近比较穷(不像集训队陈兴老师是个rich second),所以只能选择做火车从A到B.不过Alice很讨厌坐火车,火车上人比较多,比较拥挤,所以Alice有很严格的要求:火车的相邻两站间的最大距离尽可能的短,这样Alice就可以在停站的时候下车休息一下.当…

上周末学习了<A Tour of PostgreSQL Internals>的第一部分(View 1),今天我们继续打开书本,继续View 2 部分. View 2 Postgresql的系统表和数据类型 和其他大多数DBMS相比,postgresql在更大程度上使用了" 数据驱动 ". 为什么这么说呢? 按照Tom Lane的解释,原因如下: postgresql使用一套系统表描述数据库表,表中的每一列,每个索引等等: 除此以外,postgresql同样使用系统表存储数据…

中秋节假期这么快就没了,这几天还一直下雨,索性在家看看书.这次看的是Tom Lane的<A Tour of PostgreSQL Internals>.这篇小随笔就算做学习笔记了.园子里面大神多,如果有哪里讲得不对,还请各位前辈多多指教了~ 在这个ppt里面,大神Tom Lane分别从三个角度对Postgresql的内部原理进行了介绍. View 1 Postgresql进程以及内部进程间的通信 这部分比较简短,主要介绍了客户端/服务器间通信,服务器内部的通信. 1. 客户端/服务器间通信 一…

The next section covers Go's concurrency primitives. A Tour of Go Goroutines A goroutine is a lightweight thread managed by the Go runtime. go f(x, y, z) starts a new goroutine running f(x, y, z) The evaluation of f, x, y, and z happens in the curren…

/* Exercise: Loops and Functions #43 */ package main import ( "fmt" "math" ) func Sqrt(x float64) float64 { z := float64(.) s := float64() for { z = z - (z*z - x)/(*z) { break } s = z } return s } func main() { fmt.Println(Sqrt()) fmt.…

Package http serves HTTP requests using any value that implementshttp.Handler: package http type Handler interface { ServeHTTP(w ResponseWriter, r *Request) } In this example, the type Hello implements http.Handler. Visit http://localhost:4000/ to se…

最大流求混合图是否存在欧拉回路. 以下内容摘自http://www.cnblogs.com/Missa/archive/2012/12/05/2803107.html 讲的很清楚. 混合图的欧拉回路问题 欧拉回路问题. 1 定义 欧拉通路 (Euler tour)——通过图中每条边一次且仅一次,并且过每一顶点的通路. 欧拉回路 (Euler circuit)——通过图中每条边一次且仅一次,并且过每一顶点的回路. 欧拉图——存在欧拉回路的图. 2 无向图是否具有欧拉通路或回路的判定 G有欧拉通路的…

Cyclic Tour Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/65535 K (Java/Others)Total Submission(s): 1399    Accepted Submission(s): 712 Problem Description There are N cities in our country, and M one-way roads connecting them. Now Li…

Description When FJ's friends visit him on the farm, he likes to show them around. His farm comprises N (1 <= N <= 1000) fields numbered 1..N, the first of which contains his house and the Nth of which contains the big barn. A total M (1 <= M <…

Tour Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 65535/65535 K (Java/Others)Total Submission(s): 2628    Accepted Submission(s): 1285 Problem Description In the kingdom of Henryy, there are N (2 <= N <= 200) cities, with M (M <= 30000…

Sightseeing tour Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 8628   Accepted: 3636 Description The city executive board in Lund wants to construct a sightseeing tour by bus in Lund, so that tourists can see every corner of the beauti…

Farm Tour Time Limit: 1000ms Memory Limit: 65536KB This problem will be judged on PKU. Original ID: 2135 64-bit integer IO format: %lld      Java class name: Main   When FJ's friends visit him on the farm, he likes to show them around. His farm compr…

http://tour.golang.org/#1 中文版:http://go-tour-cn.appsp0t.com/#4 package main import ( "fmt" "math") func main() { fmt.Println("Happy", math.Pi, "Day")} 每个 Go 程序都是由包组成的. 程序运行的入口从包的 main方法. 这个程序使用并导入了包 "fmt" …

Farm Tour 题目: 约翰有N块地,家在1号,而N号是个仓库.农场内有M条道路(双向的),道路i连接这ai号地和bi号地,长度为ci. 约翰希望依照从家里出发,经过若干地后达到仓库.然后再返回家中.假设要求往返不能经过同一条道路两次,求參观路线总长度最小值. 算法分析: 用最短路求解然后在删除第一次最短路中的边在求解一次最短路.这样是否可行?应该立即就能找到反例证明该方法不能总得到最优结果吧. 于是我们放弃把问题当作去和回的这样的想法,转而将问题当作求从1号顶点到N号顶点的两条没有公共边的…