AtCoder Regular Contest 145
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Problem Statement
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The score of a permutation $P=(P_1,P_2,\ldots,P_{2N})$ of $(1,2,\ldots,2N)$ is defined as follows:
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Consider dividing
P
into two (not necessarily contiguous) subsequences
A = (A_1,A_2,\ldots,A_N)
and
B = (B_1,B_2,\ldots,B_N)
. The score of
P
is the maximum possible value of
\displaystyle\sum_{i=1}^{N}A_i B_i
in such a division.
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Let $M$ be the maximum among the scores of all permutations of $(1,2,\ldots,2N)$. Find the number, modulo $998244353$, of permutations of $(1,2,\ldots,2N)$ with the score of $M$.
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Constraints
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$1 \leq N \leq 2\times 10^5$- All values in 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
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Output
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Print the answer.
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样例
Input #1
2
Output #1
16
The maximum among the scores of the $24$ possible permutations, $M$, is $14$, and there are $16$ permutations with the score of $14$.
For instance, the permutation $(1,2,3,4)$ achieves $\sum _{i=1}^{N}A_i B_i = 14$ in the division $A=(1,3), B=(2,4)$.
Input #2
10000
Output #2
391163238
Print the count modulo $998244353$.
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。