AtCoder Grand Contest 021
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Problem Statement
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Takahashi has an $N \times M$ grid, with $N$ horizontal rows and $M$ vertical columns. Determine if we can place $A$ $1 \times 2$ tiles ($1$ vertical, $2$ horizontal) and $B$ $2 \times 1$ tiles ($2$ vertical, $1$ horizontal) satisfying the following conditions, and construct one arrangement of the tiles if it is possible:
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- All the tiles must be placed on the grid.
- Tiles must not stick out of the grid, and no two different tiles may intersect.
- Neither the grid nor the tiles may be rotated.
- Every tile completely covers exactly two squares.
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Constraints
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$1 \leq N,M \leq 1000$$0 \leq A,B \leq 500000$$N$,$M$,$A$and$B$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 A B
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Output
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If it is impossible to place all the tiles, print NO. Otherwise, print the following:
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YES
c_{11}...c_{1M}
:
c_{N1}...c_{NM}
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Here, $c_{ij}$ must be one of the following characters: ., <, >, ^ and v. Represent an arrangement by using each of these characters as follows:
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- When
$c_{ij}$is., it indicates that the square at the$i$-th row and$j$-th column is empty; - When
$c_{ij}$is<, it indicates that the square at the$i$-th row and$j$-th column is covered by the left half of a$1 \times 2$tile; - When
$c_{ij}$is>, it indicates that the square at the$i$-th row and$j$-th column is covered by the right half of a$1 \times 2$tile; - When
$c_{ij}$is^, it indicates that the square at the$i$-th row and$j$-th column is covered by the top half of a$2 \times 1$tile; - When
$c_{ij}$isv, it indicates that the square at the$i$-th row and$j$-th column is covered by the bottom half of a$2 \times 1$tile.
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样例
Input #1
3 4 4 2
Output #1
YES
<><>
^<>^
v<>v
This is one example of a way to place four $1 \times 2$ tiles and three $2 \times 1$ tiles on a $3 \times 4$ grid.
Input #2
4 5 5 3
Output #2
YES
<>..^
^.<>v
v<>.^
<><>v
Input #3
7 9 20 20
Output #3
NO
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。