E. Eyes Closed time limit per test 2.5 seconds memory limit per test 256 megabytes input standard input output standard output Vasya and Petya were tired of studying so they decided to play a game. Before the game begins Vasya looks at array a consis…

D. String Mark time limit per test 4 seconds memory limit per test 256 megabytes input standard input output standard output At the Byteland State University marks are strings of the same length. Mark x is considered better than y if string y is lexi…

C. Square Subsets time limit per test 4 seconds memory limit per test 256 megabytes input standard input output standard output Petya was late for the lesson too. The teacher gave him an additional task. For some array a Petya should find the number…

B. XK Segments time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output While Vasya finished eating his piece of pizza, the lesson has already started. For being late for the lesson, the teacher sug…

A. Pizza Separation time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Students Vasya and Petya are studying at the BSU (Byteland State University). At one of the breaks they decided to order…

题目链接  Eyes Closed 题意  两个人玩一个游戏,现在有两种操作: 1.两个人格子挑选一个区间,保证两个的区间不相交.在这两个区间里面各选出一个数,交换这两个数. 2.挑选一个区间,求这个区间的和的期望. 对于第一种操作,先求出两个区间的长度$len1$和$len2$,再求出两个区间的期望和$s1$和$s2$. 对于第一个区间,我们先把这个区间里的所有数(期望值)乘上$(len1 - 1)/(len1)$,再加上$s2/len1/len2$ 对于第二个区间,我们先把这个区间里的所有数…

B. Island Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/gym/100114 Description On February 30th this year astronauts from the International Space Station flew over the Pacific Ocean and took a picture, on which was discovered a pr…

C - Important RoadsTime Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://acm.hust.edu.cn/vjudge/contest/view.action?cid=88926#problem/C Description The city where Georgie lives has n junctions some of which are connected by bidirectional roads. Every d…

今天老师(orz sansirowaltz)让我们做了很久之前的一场Codeforces Round #257 (Div. 1),这里给出A~C的题解,对应DIV2的C~E. A.Jzzhu and Chocolate time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Jzzhu has a big rectangular cho…

A. The Useless Toy time limit per test:1 second memory limit per test:256 megabytes input:standard input output:standard output Walking through the streets of Marshmallow City, Slastyona have spotted some merchants selling a kind of useless toy which…