Bebras 2019 - Level 4 Question 13

Question 13

Natasha the beaver has lost her robot in a park. The park is a 3×3 area as shown below. The robot may be anywhere in its 9 unit squares.

Question illustration

Natasha can wirelessly send the robot these commands:
- UP: move up 1 square
- DOWN: move down 1 square
- LEFT: move left 1 square
- RIGHT: move right 1 square

The robot cannot pass through the walls shown as thick lines. If a command would cross a wall, the beaver remains in place waiting for the next command. Which of the following command sequences is the shortest that can help Natasha bring the robot to the square containing the star?

DOWN – LEFT – DOWN – LEFT – UP – UP
RIGHT – UP – UP – LEFT – LEFT
RIGHT – UP – RIGHT – UP – LEFT – LEFT
UP – RIGHT – UP – LEFT – LEFT