Codeforces Round 416 (Div. 2)
D
Vladik and Favorite Game
Codeforces
2100
原题
← CE →
翻译中…

This is an interactive problem.

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Vladik has favorite game, in which he plays all his free time.

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Game field could be represented as $*n* × *m*$ matrix which consists of cells of three types:

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  • «.» — normal cell, player can visit it.
  • «F» — finish cell, player has to finish his way there to win. There is exactly one cell of this type.
  • «*» — dangerous cell, if player comes to this cell, he loses.
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Initially player is located in the left top cell with coordinates $(1, 1)$.

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Player has access to $4$ buttons "U", "D", "L", "R", each of them move player up, down, left and right directions respectively.

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But it’s not that easy! Sometimes friends play game and change functions of buttons. Function of buttons "L" and "R" could have been swapped, also functions of buttons "U" and "D" could have been swapped. Note that functions of buttons can be changed only at the beginning of the game.

翻译中…

Help Vladik win the game!

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Input

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First line contains two space-separated integers $*n*$ and $*m*$ ($1 ≤ *n*, *m* ≤ 100$) — number of rows and columns respectively.

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Each of next $*n*$ lines contains $*m*$ characters describing corresponding row of field. Set of characters in field is described above.

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Guaranteed that cell with coordinates $(1, 1)$ is normal and there is at least one way from initial cell to finish cell without dangerous cells.

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Interaction

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You can press buttons no more than $2·*n*·*m*$ times.

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To press a button you should print "U", "D", "L", "R" in new line. It’s necessary to print newline character and flush output. After flushing buffer you should read answer from input data. Answer is the pair of space-separated integers $*x*$, $*y*$ — new position of player. In case, if there is no cell in direction of moving, position will not change. If after any move player lost, in other words player move to dangerous cell, then $*x*$ and $*y*$ will be equal to $- 1$.

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If after any move player is in finish or dangerous cell, then you should terminate your program.

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To finish output buffer (i. e. for operation flush) right after printing direction and newline you should do next:

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  • fflush(stdout) in C++
  • System.out.flush() in Java
  • stdout.flush() in Python
  • flush(output) in Pascal
  • read documentation for other languages.
翻译中…

Hacks

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To perform a hack you should use this format:

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n m swapLR swapUD
a_1
a_2
...
a_n

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Where $*n*$, $*m*$ — number of rows and columns in game field. $*swapLR*$ is equal to $1$ in case, when directions "L’’ and "R’’ is swapped, and equal to $0$ otherwise. $*swapUD*$ is equal to $1$, when directions "U’’ and "D’’ is swapped, and equal to $0$ otherwise. $*a*_{1}, *a*_{2}, ..., *a*_{*n*}$ — description of corresponding rows of game field.

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Note

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In first test case all four directions swapped with their opposite directions. Protocol of interaction In more convenient form:

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image

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This test could be presenter for hack in following way:

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4 3 1 1
...
**.
F*.
...

翻译中…

样例

Input #1
4 3
...
**.
F*.
...
1 1
1 2
1 3
1 3
2 3
3 3
4 3
4 2
4 1
3 1
Output #1
R
L
L
D
U
U
U
R
R
D
InputCopy OutputCopy
题目信息
题号
811D
时间限制
2 s
内存限制
256 MB
标签
构造
DFS 及类似
图论
交互题

题面与样例版权归 Codeforces 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。