B. New Year and Ascent Sequence 题意:定义上升序列Ascent,在一组序列A中,存在1<i<j<n,使得Ai<Aj.现在给定n个序列,求n个序列两两组合的n^2个组合序列中,有多少个组合是Ascent序列.. 思路: 用两个MAX,MIN数组分别记录下每个序列的最大值和最小值,然后把最大值进行排序.每次做一遍二分,取每个数组中的最小值到所有数组中的最大值中找有多少个数比它大,这样组合的新序列便是满足Ascent性质.如果本身这个序列就已经满足Asce…

(CodeForces - 5C)Longest Regular Bracket Sequence time limit per test:2 seconds memory limit per test:256 megabytes input:standard input output:standard output This is yet another problem dealing with regular bracket sequences. We should remind you t…

[Codeforces 865C]Gotta Go Fast(期望dp+二分答案) 题面 一个游戏一共有n个关卡,对于第i关,用a[i]时间通过的概率为p[i],用b[i]通过的时间为1-p[i],每通过一关后可以选择继续下一关或者时间清0并从第一关开始,先要求通过所有关卡的时间和不能超过R才算彻底通关,问直到彻底通关位置的游戏时间的期望值为多少 分析 二分从头开始通关的用时期望mid 设\(dp[i][j]\)表示通前i关,当前时间为j的期望,倒推期望. 若超时重新开始,则\(dp[i][j]…

E. Restoring Increasing Sequence time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Peter wrote on the board a strictly increasing sequence of positive integers a1, a2, ..., an. Then Vasil rep…

A. Infinite Sequence time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Consider the infinite sequence of integers: 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 5.... The sequence is built in the…

Problem F. Door LockTime Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/gym/100500/attachments Description It was a beautiful night at Yekaterinburg, the sky was crystal clear with no clouds, and the view of the moon and the stars was…

http://codeforces.com/contest/749/problem/D 题意:有几个人在拍卖场竞价,一共有n次喊价,有q个询问,每一个询问有一个num,接下来num个人从这次拍卖中除去,问对于每一个询问减掉num个人后是谁赢了拍卖,最小的价格是多少. 思路:昨晚不会做.想法好神奇(我太弱).对于每个人用 set-S 装起来其每次喊价的下标,然后用一个数组order按价格从大到小的顺序将每个人装起来,对于每一个询问,把这num个人丢到一个 set-s 里面,然后在order里面找没…

C. Cellular Network time limit per test 3 seconds memory limit per test 256 megabytes input standard input output standard output You are given n points on the straight line — the positions (x-coordinates) of the cities and m points on the same line…

Flipping Parentheses 题目连接: http://codeforces.com/gym/100803/attachments Description A string consisting only of parentheses '(' and ')' is called balanced if it is one of the following. • A string "()" is balanced. • Concatenation of two balance…

Friends and Subsequences 题目链接: http://acm.hust.edu.cn/vjudge/contest/121333#problem/H Description Mike and !Mike are old childhood rivals, they are opposite in everything they do, except programming. Today they have a problem they cannot solve on the…