AtCoder Regular Contest 212 (Div. 2)
C
ABS Ball
AtCoder
⌀ 1825
原题
← BD →
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Problem Statement

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There are $N$ white balls. First, you paint each ball red or blue.

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Then, you place these $N$ red or blue painted balls in one of $M$ distinguishable boxes.

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Let $a_i$ and $b_i$ be the number of red and blue balls in the $i$-th box, respectively.

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Find the sum, modulo $998244353$, of $\prod_{1\leq i \le M}|a_i-b_i|$ over all ways to place the balls.

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Here, two ways of placing balls are different if and only if at least one of $a_i$ and $b_i$ is different for some $i$.

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Particularly, balls are not distinguished from each other.

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Constraints

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  • $1 \le N,M \le 10^7$
  • All input values are integers.
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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

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Output

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Output the answer.

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样例

Input #1
2 1
Output #1
4
There are three ways to place balls in box $1$. If you place one red ball and one blue ball, $|a_1-b_1|=0$. If you place two red balls or two blue balls, $|a_1-b_1|=2$. Therefore, the answer is $0 + 2 + 2 = 4$.
Input #2
5 7
Output #2
0
Input #3
10000000 5000000
Output #3
965172629
题目信息
题号
arc212_c
时间限制
2 s
内存限制
1024 MB

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