C. Back and Forth

    传统题 2000ms 256MiB

Back and Forth

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Problem

Dolphin resides in two-dimensional Cartesian plane, with the positive xx-axis pointing right and the positive yy-axis pointing up.
Currently, he is located at the point (sx,sy)(sx,sy). In each second, he can move up, down, left or right by a distance of 11.
Here, both the xx- and yy-coordinates before and after each movement must be integers.
He will first visit the point (tx,ty)(tx,ty) where sx<txsx < tx and sy<tysy < ty, then go back to the point (sx,sy)(sx,sy), then visit the point (tx,ty)(tx,ty) again, and lastly go back to the point (sx,sy)(sx,sy).
Here, during the whole travel, he is not allowed to pass through the same point more than once, except the points (sx,sy)(sx,sy) and (tx,ty)(tx,ty).
Under this condition, find a shortest path for him.

Constraints

  • 1000sx<tx1000-1000 ≤ sx < tx ≤ 1000
  • 1000sy<ty1000-1000 ≤ sy < ty ≤ 1000
  • sx,sy,txsx,sy,tx and tyty are integers.

Input

The input is given from Standard Input in the following format:

sxsx sysy txtx tyty

Output

Print a string SS that represents a shortest path for Dolphin.
The ii-th character in SS should correspond to his ii-th movement.
The directions of the movements should be indicated by the following characters:

  • U: Up
  • D: Down
  • L: Left
  • R: Right

If there exist multiple shortest paths under the condition, print any of them.

Example : 1. in

0 0 1 2

Example : 1. out

UURDDLLUUURRDRDDDLLU

One possible shortest path is:

  • Going from (sx,sy)(sx,sy) to (tx,ty)(tx,ty) for the first time: (0,0)(0,0)(0,1)(0,1)(0,2)(0,2)(1,2)(1,2)
  • Going from (tx,ty)(tx,ty) to (sx,sy)(sx,sy) for the first time: (1,2)(1,2)(1,1)(1,1)(1,0)(1,0)(0,0)(0,0)
  • Going from (sx,sy)(sx,sy) to (tx,ty)(tx,ty) for the second time: (0,0)(0,0)(1,0)(-1,0)(1,1)(-1,1)(1,2)(-1,2)(1,3)(-1,3)(0,3)(0,3)(1,3)(1,3)(1,2)(1,2)
  • Going from (tx,ty)(tx,ty) to (sx,sy)(sx,sy) for the second time: (1,2)(1,2)(2,2)(2,2)(2,1)(2,1)(2,0)(2,0)(2,1)(2,-1)(1,1)(1,-1)(0,1)(0,-1)(0,0)(0,0)

Example : 2. in

-2 -2 1 1

Example : 2. out

UURRURRDDDLLDLLULUUURRURRDDDLLDL

AtCoder-ABC051

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ACM/ICPC
题目
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开始于
2024-11-17 19:00
结束于
2024-11-17 21:00
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