#P14674. [ICPC 2025 Seoul R] Fair Problemset
[ICPC 2025 Seoul R] Fair Problemset
题目描述
This problem adopts exactly the same definition of Fair Problemset as Problem M, "Triple Fairness".
ICPC is a team competition. Each team has three members. At the beginning of a contest, most teams divide the problem evenly. They use one of two common methods to distribute problems:
- Sequential Distribution: Each member takes a contiguous block of problems from the set of problems. Specifically, the first member takes problems , the second member takes problems , and the third member takes problems .
- Jump Distribution: Each member takes problems with indices that have the same remainder when divided by 3 from the set of problems. Specifically, the first member takes problems , the second member takes problems , and the third member takes problems .
The ICPC Seoul Regional Contest Scientific Committee must prepare a problemset consisting of problems. The difficulty of each problem is represented by an integer from 1 to , inclusive. For each difficulty, there are exactly three problems with that difficulty. Thus, the arrangement of difficulties in the problemset can be viewed as a difficulty sequence of length containing three problems of each of the difficulty levels.
To prevent any advantage or disadvantage for a team based on their chosen problem distribution method, the ICPC Seoul Regional Contest Scientific Committee has defined a standard called a Fair Problemset. A difficulty sequence of length is called a Fair Problemset if it satisfies both of the following conditions:
- Sequential Distribution Fairness: When using Sequential Distribution, for every difficulty level (), each of the three members receives exactly one problem with difficulty .
- Jump Distribution Fairness: When using Jump Distribution, for every difficulty level (), each of the three members receives exactly one problem with difficulty .
In other words, regardless of which of the two methods is chosen, each team member must be assigned exactly one problem for each difficulty level from 1 to , inclusive.
Given a positive integer , write a program to find the number of Fair Problemset sequences of length for each .
输入格式
Your program is to read from standard input. The input consists of exactly one line. The line contains two integers, and (; ; is a prime number).
输出格式
Your program is to write to standard output. You should print exactly lines. On the -th line (), print the number of Fair Problemset sequences of length , modulo .
2 993244853
1
2
3 998244353
1
2
12
提示
Here are Fair Problemset sequences of length ()
i. 1 2 3 2 3 1 3 1 2
ii. 1 2 3 3 1 2 2 3 1
iii. 1 3 2 2 1 3 3 2 1
iv. 1 3 2 3 2 1 2 1 3
v. 2 1 3 1 3 2 3 2 1
vi. 2 1 3 3 2 1 1 3 2
vii. 2 3 1 1 2 3 3 1 2
viii. 2 3 1 3 1 2 1 2 3
ix. 3 1 2 1 2 3 2 3 1
x. 3 1 2 2 3 1 1 2 3
xi. 3 2 1 1 3 2 2 1 3
xii. 3 2 1 2 1 3 1 3 2