题目描述 Like all bovines, Farmer John's cows speak the peculiar 'Cow'language. Like so many languages, each word in this language comprisesa sequence of upper and lowercase letters (A-Z and a-z).  A wordis valid if and only if each ordered pair of adjac…

n<=250个大写字母和m<=250个小写字母,给p<=200个合法相邻字母,求用这些合法相邻字母的规则和n+m个字母能合成多少合法串,答案mod 97654321. 什么鬼膜数.. f(i,j,k)--i个大写字母,j个小写字母,最后一个字母是k,,其中k是小写字母,p是能接在k前面的任意字母,k是大写字母的话同理. 这样复杂度是n*m*26*26?假的!i,j确定后只有p种合法转移,所以就n*m*p. trick:记得算i=0和j=0的情况!!! #include<cstrin…

2272: [Usaco2011 Feb]Cowlphabet 奶牛文字 Time Limit: 10 Sec  Memory Limit: 128 MBSubmit: 138  Solved: 97[Submit][Status][Discuss] Description Like all bovines, Farmer John's cows speak the peculiar 'Cow'language. Like so many languages, each word in this…

题目描述 Farmer John's N (1 <= N <= 100,000) cows are lined up in a row andnumbered 1..N. The cows are conducting another one of their strangeprotests, so each cow i is holding up a sign with an integer A_i(-10,000 <= A_i <= 10,000). FJ knows the…

[USACO2002 Feb]奶牛自行车队 Time Limit: 1000 ms Memory Limit: 131072 KBytes Description N 头奶牛组队参加自行车赛.车队在比赛时排成一列,需要绕场S 圈.由于空气阻力的作用,领队奶牛消耗的体力要比后面的多.每头奶牛的初始体力都是相同的,记作M,体力减为负数的奶牛只能中途退赛,体力也不会在比赛途中恢复,但最后只要有一位队员到达终点就算完成了比赛. 比赛最小的单位时间是分钟.车队在每分钟必须绕赛场整数圈,最少是每分钟一圈.如…

康托展开 裸的康托展开&逆康托展开 康托展开就是一种特殊的hash,且是可逆的…… 康托展开计算的是有多少种排列的字典序比这个小,所以编号应该+1:逆运算同理(-1). 序列->序号:(康托展开) 对于每个数a[i],数比它小的数有多少个在它之前没出现,记为b[i],$ans=1+\sum b[i]* (n-i)!$ 序号->序列:(逆康托展开) 求第x个排列所对应的序列,先将x-1,然后对于a[i],$\left\lfloor \frac{x}{(n-i)!} \right\rflo…

2274: [Usaco2011 Feb]Generic Cow Protests Time Limit: 10 Sec  Memory Limit: 128 MBSubmit: 196  Solved: 122[Submit][Status] Description Farmer John's N (1 <= N <= 100,000) cows are lined up in a row and numbered 1..N. The cows are conducting another…

3301: [USACO2011 Feb] Cow Line Time Limit: 10 Sec  Memory Limit: 128 MBSubmit: 67  Solved: 39[Submit][Status] Description The N (1 <= N <= 20) cows conveniently numbered 1...N are playing yet another one of their crazy games with Farmer John. The co…

3300: [USACO2011 Feb]Best Parenthesis Time Limit: 10 Sec  Memory Limit: 128 MBSubmit: 89  Solved: 42[Submit][Status] Description Recently, the cows have been competing with strings of balanced parentheses and comparing them with each other to see who…

3301: [USACO2011 Feb] Cow Line Time Limit: 10 Sec  Memory Limit: 128 MBSubmit: 82  Solved: 49[Submit][Status][Discuss] Description The N (1 <= N <= 20) cows conveniently numbered 1...N are playing yet another one of their crazy games with Farmer Joh…