codeforces#P1227F1. Wrong Answer on test 233 (Easy Version)
Wrong Answer on test 233 (Easy Version)
Description
This is the easier version of the problem. In this version $1 \le n \le 2000$. You can hack this problem only if you solve and lock both problems.
The problem is about a test containing $n$ one-choice-questions. Each of the questions contains $k$ options, and only one of them is correct. The answer to the $i$-th question is $h_{i}$, and if your answer of the question $i$ is $h_{i}$, you earn $1$ point, otherwise, you earn $0$ points for this question. The values $h_1, h_2, \dots, h_n$ are known to you in this problem.
However, you have a mistake in your program. It moves the answer clockwise! Consider all the $n$ answers are written in a circle. Due to the mistake in your program, they are shifted by one cyclically.
Formally, the mistake moves the answer for the question $i$ to the question $i \bmod n + 1$. So it moves the answer for the question $1$ to question $2$, the answer for the question $2$ to the question $3$, ..., the answer for the question $n$ to the question $1$.
We call all the $n$ answers together an answer suit. There are $k^n$ possible answer suits in total.
You're wondering, how many answer suits satisfy the following condition: after moving clockwise by $1$, the total number of points of the new answer suit is strictly larger than the number of points of the old one. You need to find the answer modulo $998\,244\,353$.
For example, if $n = 5$, and your answer suit is $a=[1,2,3,4,5]$, it will submitted as $a'=[5,1,2,3,4]$ because of a mistake. If the correct answer suit is $h=[5,2,2,3,4]$, the answer suit $a$ earns $1$ point and the answer suite $a'$ earns $4$ points. Since $4 > 1$, the answer suit $a=[1,2,3,4,5]$ should be counted.
The first line contains two integers $n$, $k$ ($1 \le n \le 2000$, $1 \le k \le 10^9$) — the number of questions and the number of possible answers to each question.
The following line contains $n$ integers $h_1, h_2, \dots, h_n$, ($1 \le h_{i} \le k)$ — answers to the questions.
Output one integer: the number of answers suits satisfying the given condition, modulo $998\,244\,353$.
Input
The first line contains two integers $n$, $k$ ($1 \le n \le 2000$, $1 \le k \le 10^9$) — the number of questions and the number of possible answers to each question.
The following line contains $n$ integers $h_1, h_2, \dots, h_n$, ($1 \le h_{i} \le k)$ — answers to the questions.
Output
Output one integer: the number of answers suits satisfying the given condition, modulo $998\,244\,353$.
Samples
3 3
1 3 1
9
5 5
1 1 4 2 2
1000
Note
For the first example, valid answer suits are $[2,1,1], [2,1,2], [2,1,3], [3,1,1], [3,1,2], [3,1,3], [3,2,1], [3,2,2], [3,2,3]$.