デンソークリエイトプログラミングコンテスト2023(AtCoder Beginner Contest 309)
Ex
Simple Path Counting Problem
AtCoder
⌀ 3029
原题
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Problem Statement

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We have a grid with $N$ rows and $M$ columns. We denote by $(i,j)$ the cell in the $i$-th row from the top and $j$-th column from the left.

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You are given integer sequences $A=(A_1,A_2,\dots,A_K)$ and $B=(B_1,B_2,\dots,B_L)$ of lengths $K$ and $L$, respectively.

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Find the sum, modulo $998244353$, of the answers to the following question over all integer pairs $(i,j)$ such that $1 \le i \le K$ and $1 \le j \le L$.

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  • A piece is initially placed at $(1,A_i)$. How many paths are there to take it to $(N,B_j)$ by repeating the following move $(N-1)$ times?
  • Let $(p,q)$ be the piece's current cell. Move it to $(p+1,q-1),(p+1,q)$, or $(p+1,q+1)$, without moving it outside the grid.
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Constraints

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  • $1 \le N \le 10^9$
  • $1 \le M,K,L \le 10^5$
  • $1 \le A_i,B_j \le M$
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Input

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The input is given from Standard Input in the following format:

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N M K L
A_1 A_2 \dots A_K
B_1 B_2 \dots B_L

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Output

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Print the answer.

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样例

Input #1
3 4 1 2
1
1 2
Output #1
4
For $(i,j)=(1,1)$, the following two paths are possible: - $(1,1) \rightarrow (2,1) \rightarrow (3,1)$ - $(1,1) \rightarrow (2,2) \rightarrow (3,1)$ For $(i,j)=(1,2)$, the following two paths are possible: - $(1,1) \rightarrow (2,1) \rightarrow (3,2)$ - $(1,1) \rightarrow (2,2) \rightarrow (3,2)$ Thus, the answer is $2 + 2 =4$.
Input #2
5 8 4 5
3 1 4 1
2 7 1 8 2
Output #2
137
Input #3
883671387 87719 10 12
86879 64174 47274 41688 17713 50897 53989 7210 30894 5714
60358 28835 48036 48450 67149 36558 35929 69025 77539 19195 60762 60721
Output #3
941873621
题目信息

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