AtCoder Grand Contest 046
B
Extension
AtCoder
⌀ 1588
原题
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Problem Statement

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We have a grid with $A$ horizontal rows and $B$ vertical columns, with the squares painted white. On this grid, we will repeatedly apply the following operation:

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  • Assume that the grid currently has $a$ horizontal rows and $b$ vertical columns. Choose "vertical" or "horizontal".
  • If we choose "vertical", insert one row at the top of the grid, resulting in an $(a+1) \times b$ grid.
    • If we choose "horizontal", insert one column at the right end of the grid, resulting in an $a \times (b+1)$ grid.
  • Then, paint one of the added squares black, and the other squares white.
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Assume the grid eventually has $C$ horizontal rows and $D$ vertical columns. Find the number of ways in which the squares can be painted in the end, modulo $998244353$.

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Constraints

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  • $1 \leq A \leq C \leq 3000$
  • $1 \leq B \leq D \leq 3000$
  • $A$, $B$, $C$, and $D$ 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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A B C D

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Output

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Print the number of ways in which the squares can be painted in the end, modulo $998244353$.

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样例

Input #1
1 1 2 2
Output #1
3
Any two of the three squares other than the bottom-left square can be painted black.
Input #2
2 1 3 4
Output #2
65
Input #3
31 41 59 265
Output #3
387222020
题目信息
题号
agc046_b
时间限制
2 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。