9168: ABC282 —— G - Similar Permutation
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Description
Below, a permutation of $(1,2,\ldots,N)$ is simply called a permutation.
For two permutations $A=(A_1,A_2,\ldots,A_N),B=(B_1,B_2,\ldots,B_N)$, let us define their similarity as the number of integers $i$ between $1$ and $N-1$ such that:
- $(A_{i+1}-A_i)(B_{i+1}-B_i)>0$.
Find the number, modulo a prime number $P$, of pairs of permutations $(A,B)$ whose similarity is $K$.
For two permutations $A=(A_1,A_2,\ldots,A_N),B=(B_1,B_2,\ldots,B_N)$, let us define their similarity as the number of integers $i$ between $1$ and $N-1$ such that:
- $(A_{i+1}-A_i)(B_{i+1}-B_i)>0$.
Find the number, modulo a prime number $P$, of pairs of permutations $(A,B)$ whose similarity is $K$.
Input
The input is given from Standard Input in the following format:
```
$N$ $K$ $P$
```
```
$N$ $K$ $P$
```
Output
Print the answer.
Constraints
- $2\leq N \leq 100$
- $0\leq K \leq N-1$
- $10^8 \leq P \leq 10^9$
- $P$ is a prime number.
- All values in the input are integers.
- $0\leq K \leq N-1$
- $10^8 \leq P \leq 10^9$
- $P$ is a prime number.
- All values in the input are integers.
Sample 1 Input
3 1 282282277
Sample 1 Output
16
For instance, below is a pair of permutations that satisfies the condition.
- A=(1,2,3)
- B=(1,3,2)
Here, we have $(A_2−A_1)(B_2−B_1)>0$ and $(A_3−A_2)(B_3−B_2)<0$, so the similarity of A and B is 1.
Sample 2 Input
50 25 998244353
Sample 2 Output
131276976