No.1759 Silver Tour
タグ : / 解いたユーザー数 16
作問者 :
PCTprobability
Problem Statement
There is a shogi board with $H \times W$ rows and columns and $1$ silver general piece.
As shown in Figure $1$, a silver general can move to the $3$ squares in front of it and to the squares diagonally behind it. However, the destination must be inside the board.
More precisely, denoting the square in the $i$-th row from the top and the $j$-th column from the left by $(i,j)$, a silver placed on $(i,j)$ can move to $(i-1,j-1),(i-1,j),(i-1,j+1),(i+1,j-1),(i+1,j+1)$.
Moving the silver general so that the following condition is satisfied is called a "silver full-board tour".
- Place the silver on one of the squares in the bottom row of the board, that is, one of $(H,j)$ $(1 \leq j \leq W)$, and move the silver so that it passes through all squares without passing through the same square more than once.
For example, the moves shown in Figure $2$ are one example of a silver full-board tour when $H = W = 2$.
Find the number of possible silver full-board tours, modulo $M$.
Here, two silver full-board tours are considered different if they differ when the moves are viewed as sequences of squares.
Constraints
- All inputs are integers.
- $1 \leq H \leq 50$
- $1 \leq W \leq 50$
- $9 \times 10^8 \leq M \leq 10^9$
Input
$H\ W\ M$
Output
Output the answer in $1$ line.
Sample
Sample 1
Input
2 2 998244353
Output
2
The silver full-board tours satisfying the condition are the one shown in Figure $2$ and its left-right mirror image, for a total of $2$.
Sample 2
Input
9 9 998244353
Output
0
On a $9 \times 9$ shogi board, a silver full-board tour is impossible, so no moves satisfying the condition exist.
Sample 3
Input
6 5 924844033
Output
60
Sample 3
Input
50 50 1000000000
Output
999575486
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