# Leetcode 865 Solution

https://leetcode.com/problems/robot-room-cleaner

## Solution

``````# """
# This is the robot's control interface.
# You should not implement it, or speculate about its implementation
# """
#class Robot:
#    def move(self):
#        """
#        Returns true if the cell in front is open and robot moves into the cell.
#        Returns false if the cell in front is blocked and robot stays in the current cell.
#        :rtype bool
#        """
#
#    def turnLeft(self):
#        """
#        Robot will stay in the same cell after calling turnLeft/turnRight.
#        Each turn will be 90 degrees.
#        :rtype void
#        """
#
#    def turnRight(self):
#        """
#        Robot will stay in the same cell after calling turnLeft/turnRight.
#        Each turn will be 90 degrees.
#        :rtype void
#        """
#
#    def clean(self):
#        """
#        Clean the current cell.
#        :rtype void
#        """

class Solution:
def cleanRoom(self, robot):
"""
:type robot: Robot
:rtype: None
"""
visited = set()

def dfs(i, j, direction):
nonlocal robot
nonlocal visited

key = (i, j)
if key in visited:
return

robot.clean()

new_direction = direction
for _ in range(4):
if robot.move():
if new_direction == 0:
dfs(i - 1, j, new_direction)
elif new_direction == 1:
dfs(i, j + 1, new_direction)
elif new_direction == 2:
dfs(i + 1, j, new_direction)
elif new_direction == 3:
dfs(i, j - 1, new_direction)
else:
raise Exception("Unexpected direction {}".format(new_direction))

robot.turnLeft()
robot.turnLeft()
robot.move()
robot.turnLeft()
robot.turnLeft()

robot.turnRight()
new_direction = (new_direction + 1) % 4

dfs(0, 0, 0)
``````