message: Update robot-room-cleaner.py
diff: @@ -17,19 +17,16 @@ class Solution(object):
  robot.turnRight()
  def dfs(pos, robot, d, lookup):
  - if pos in lookup:
  - return
  - lookup.add(pos)
  -
  robot.clean()
  for _ in directions:
  + new_pos = (pos[0]+directions[d][0],
  + pos[1]+directions[d][1])
  + if new_pos not in lookup:
  + lookup.add(new_pos)
  if robot.move():
  - dfs((pos[0]+directions[d][0],
  - pos[1]+directions[d][1]),
  - robot, d, lookup)
  + dfs(new_pos, robot, d, lookup)
  goBack(robot)
  robot.turnRight()
  d = (d+1) % len(directions)
  dfs((0, 0), robot, 0, set())
  -
  