Peaks ( Gym 100365H ) 这题nk做法还挺正常的..后面那个循环就很恶心了 考虑 dp[i][j] 表示长度为i的排列,恰好有k个峰的方案数量. 然后转移就是把 i 插入 i-1 的排列. i显然是i-1的排列里面最大的数,然后插入就只有两种情况: 插入在峰的左右,由于峰不可能相邻,所以可以插入在 2j 个位置 插入在爬山的时候,那么峰的数量+1 $ dp[i][j] = 2j\times dp[i-1][j] + ( i - 2(j - 1) )dp[i-1][j-1] $…

 Gym 101047M Removing coins in Kem Kadrãn Time Limit:2000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Practice Description standard input/output Andréh and his friend Andréas are board-game aficionados. They know many of their friend…

 Gym 101047K Training with Phuket's larvae Time Limit:2000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Practice Description standard input/output Thai cuisine is known for combining seasonings so that every dish has flavors that are…

Gym 101047E Escape from Ayutthaya Time Limit:2000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u  Practice  Description standard input/output Ayutthaya was one of the first kingdoms in Thailand, spanning since its foundation in 1350 to…

 Gym 101047B  Renzo and the palindromic decoration Time Limit:2000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Practice Description standard input/output At the ruins of Wat Phra Si Sanphet (วดพระศรสรรเพชญ), one can find famous inscr…

题目链接 http://codeforces.com/gym/101102/problem/J Description standard input/output You are given an array A of integers of size N, and Q queries. For each query, you will be given a set of distinct integers S and two integers L and R that represent a…

题目链接 http://codeforces.com/gym/100917/problem/J Description standard input/outputStatements The jury of Berland regional olympiad in informatics does not trust to contest management systems, so the Berland regional programming contest is judged by th…

题目链接 http://codeforces.com/gym/100917/problem/D problem description Famous Berland coder and IT manager Linus Gates announced his next proprietary open-source system "Winux 10.04 LTS" In this system command "dir -C" prints list of all…

题目链接 http://codeforces.com/gym/101102/problem/D problem  description Given an R×C grid with each cell containing an integer, find the number of subrectangles in this grid that contain only one distinct integer; this means every cell in a subrectangle…

题目链接 http://codeforces.com/gym/101102/problem/C problem description Judge Bahosain was bored at ACM AmrahCPC 2016 as the winner of the contest had the first rank from the second hour until the end of the contest. Bahosain is studying the results of t…