Two Arrays

2000ms

262144K

Description:

You are given two arrays $$$a_1, a_2, \dots , a_n$$$ and $$$b_1, b_2, \dots , b_m$$$. Array $$$b$$$ is sorted in ascending order ($$$b_i < b_{i + 1}$$$ for each $$$i$$$ from $$$1$$$ to $$$m - 1$$$).

You have to divide the array $$$a$$$ into $$$m$$$ consecutive subarrays so that, for each $$$i$$$ from $$$1$$$ to $$$m$$$, the minimum on the $$$i$$$-th subarray is equal to $$$b_i$$$. Note that each element belongs to exactly one subarray, and they are formed in such a way: the first several elements of $$$a$$$ compose the first subarray, the next several elements of $$$a$$$ compose the second subarray, and so on.

For example, if $$$a = [12, 10, 20, 20, 25, 30]$$$ and $$$b = [10, 20, 30]$$$ then there are two good partitions of array $$$a$$$:

$$$[12, 10, 20], [20, 25], [30]$$$;
$$$[12, 10], [20, 20, 25], [30]$$$.

You have to calculate the number of ways to divide the array $$$a$$$. Since the number can be pretty large print it modulo 998244353.

Input:

The first line contains two integers $$$n$$$ and $$$m$$$ ($$$1 \le n, m \le 2 \cdot 10^5$$$) — the length of arrays $$$a$$$ and $$$b$$$ respectively.

The second line contains $$$n$$$ integers $$$a_1, a_2, \dots , a_n$$$ ($$$1 \le a_i \le 10^9$$$) — the array $$$a$$$.

The third line contains $$$m$$$ integers $$$b_1, b_2, \dots , b_m$$$ ($$$1 \le b_i \le 10^9; b_i < b_{i+1}$$$) — the array $$$b$$$.

Output:

In only line print one integer — the number of ways to divide the array $$$a$$$ modulo 998244353.

Sample Input:

6 3
12 10 20 20 25 30
10 20 30

Sample Output:

Sample Input:

4 2
1 3 3 7
3 7

Sample Output:

Sample Input:

8 2
1 2 2 2 2 2 2 2
1 2

Sample Output:

Informação

Provedor Codeforces

Código CF1366E