AtCoder Grand Contest 061
F
Perfect Strings
AtCoder
⌀ 4084
原题
← E→
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Problem Statement

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There are positive integers $N$ and $M$.

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A binary string $s$ is called good if all of the followings are satisfied:

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  • $s$ is non-empty.
  • The number of 1s in $s$ is a multiple of $N$.
  • The number of 0s in $s$ is a multiple of $M$.
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A good string is called perfect if it doesn't contain shorter good (contiguous) substrings. For example, if $N = 3$ and $M = 2$, then strings 111, 00 and 10101 are perfect, but 0000 and 11001 are not.

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One can show that for any $N, M$ the number of perfect strings is finite. Find this number modulo $998\,244\,353$.

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Constraints

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  • $1 \leq N, M \leq 40$
  • All values in the input are integers.
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Input

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Input is given from Standard Input in the following format:

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N M

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Output

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Print the answer.

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样例

Input #1
2 2
Output #1
4
The perfect strings are `00`, `0101`, `1010`, `11`.
Input #2
3 2
Output #2
7
The perfect strings are `00`, `01011`, `01101`, `10101`, `10110`, `11010`, `111`.
Input #3
23 35
Output #3
212685109
题目信息
题号
agc061_f
时间限制
10 s
内存限制
1024 MB

题面与样例版权归 AtCoder 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。