CF914H.Ember and Storm's Tree Game
普及/提高-
通过率:0%
AC君温馨提醒
该题目为【codeforces】题库的题目,您提交的代码将被提交至codeforces进行远程评测,并由ACGO抓取测评结果后进行展示。由于远程测评的测评机由其他平台提供,我们无法保证该服务的稳定性,若提交后无反应,请等待一段时间后再进行重试。
题目描述
Ember and Storm play a game. First, Ember picks a labelled tree T of n vertices, such that the degree of every vertex is at most d . Then, Storm picks two distinct vertices u and v in this tree and writes down the labels of the vertices in the path from u to v in a sequence a1,a2... ak . Finally, Ember picks any index i ( 1<=i<k ) in the array. Now he performs one of the following two operations exactly once:
- flip the subrange [i+1,k] and add ai to it. After this, the sequence becomes a1,... ai,ak+ai,ak−1+ai,... ai+1+ai
- negate the subrange [i+1,k] and add ai to it. i.e., the array becomes a1,... ai,−ai+1+ai,−ai+2+ai,...−ak+ai
Ember wins if the array is monotonically increasing or decreasing after this. Otherwise Storm wins.
The game can be described by the tuple (T,u,v,i,op) where op is «flip» or «negate» depending on the action Ember chose in the last turn. Find the number of tuples that can occur if Ember and Storm play optimally. When they play optimally, if there are multiple moves by which they are guaranteed to win, then they may play any of the winning moves. Otherwise, if someone loses no matter what they play, then they may play any of the possible moves.
Report the answer modulo m .
输入格式
The input consists of a single line containing three integers n , d and m ( 2<=n<=200,1<=d<n,1<=m<=2⋅109 ).
输出格式
Print a single number — the number of possible tuples if Ember and Storm play as described, modulo m .
输入输出样例
输入#1
2 1 1000000007
输出#1
4
输入#2
3 1 250
输出#2
0
输入#3
3 2 100
输出#3
36
说明/提示
In the first sample case, there is only one possible tree. There are two possible paths, 1 to 2 and 2 to 1 . For both paths, i can only be 1 , and op can take both possibilities. Therefore, the answer is 4 .
In the second sample, there are no possible trees.
In the third sample, there are three possible trees.