AtCoder Regular Contest 143
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Problem Statement
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Given a positive integer $N$, find the number, modulo $998244353$, of subsets $S$ of $\{1, 2, \ldots, N\}$ that satisfy the following condition.
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- Every positive integer at most
$N$can be represented as the sum of some distinct elements of$S$, and there are at most two such representations.
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Constraints
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$1 \leq N \leq 1500$
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Input
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Input is given from Standard Input in the following format:
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N
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Output
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Print the answer.
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样例
Input #1
3
Output #1
2
The subsets $\{1,2\}$ and $\{1,2,3\}$ satisfy the condition.
Input #2
5
Output #2
5
Input #3
1000
Output #3
742952024
题目信息
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。