AtCoder Grand Contest 021
C
Tiling
AtCoder
⌀ 2886
原题
← BD →
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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 $c_{ij}$ is v, 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
题号
agc021_c
时间限制
2 s
内存限制
256 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。