#522 · #489 · Robot Room Cleaner(扫地机器人)

This is an interactive problem. A robot can move() (returns whether the move succeeded), turnLeft(), turnRight() and clean(). Given only its API, clean an entire room. The room is a grid with obstacles, and the robot starts somewhere facing up. Constraints: the room is at most 1000 cells; the robot's start position is unknown to you.