7551: [CSES Problem Set] Array Description
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Description
You know that an array has $n$ integers between $1$ and $m$, and the absolute difference between two adjacent values is at most $1$.
Given a description of the array where some values may be unknown, your task is to count the number of arrays that match the description.
Given a desc
Input
The first input line has two integers $n$ and $m$: the array size and the upper bound for each value.
The next line has $n$ integers $x_1,x_2,\dots,x_n$: the contents of the array. Value $0$ denotes an unknown value.
The next line has $n$ integers $x_1,x_2,\dots,x_n$: the contents of the array. Value $0$ denotes an unknown value.
Output
Print one integer: the number of arrays modulo $10^9+7$.
Constraints
$1≤n≤10^5$
$1 \le m \le 100$
$0 \le x_i \le m$
$1 \le m \le 100$
$0 \le x_i \le m$
Sample 1 Input
3 5
2 0 2
Sample 1 Output
3
The arrays [2,1,2], [2,2,2] and [2,3,2] match the description.