Optimize the elevator controller

elevators.py

"""
Elevator Exercise.

Edit the ElevatorController implementation, focusing on
the ElevatorController.call(Passenger) method.

Run the elevator script try to increase your score.

python elevators.py
> score: 51
"""


class Elevator(object):
    """Represent an elevator."""

    def __init__(self, name, floor=0):
        """Initialize the elvator."""
        self.name = name
        self.floor = floor
        self.passengers = []
        self.destinations = []
        self.points = 0

    @property
    def direction(self):
        """Return the current direction of the elevator."""
        if self.destinations:
            if self.destinations[0] > self.floor:
                return 'up'
            elif self.destinations[0] < self.floor:
                return 'down'
        return 'still'

    def add_destination(self, destination):
        """Add a new destination to the destination queue."""
        self.destinations.append(destination)

        if self.direction == 'up':
            self.destinations.sort()
        else:
            self.destinations.sort(reverse=True)

    def distance(self, destination):
        """Return the current distance from a given floor."""
        return abs(self.floor - destination)

    def load(self, passenger):
        """A paslsenger enters the elevator and presses the destination."""
        print '{}: Loading passenger at floor {} going to {}'.format(
            self.name,
            self.floor,
            passenger.destination
        )
        self.passengers.append(passenger)
        self.add_destination(passenger.destination)
        self.points += 1

    def drop(self, passenger):
        """Drop a passenger."""
        self.passengers.remove(passenger)
        print '{}: Droping passenger at floor {}'.format(self.name, self.floor)
        self.points += 1

    def tick(self):
        """Rendering cycle."""
        # Elevator arrive at one of its destinations
        if self.destinations and self.floor == self.destinations[0]:
            self.destinations.pop(0)

        # check and dorp any passenger who arrived at its destination
        for passenger in self.passengers:
            if passenger.has_arrived(self.floor):
                self.drop(passenger)

        # If the direction is up, move the elevator up
        if self.direction == 'up':
            self.floor += 1

        # If the direction is down, move the elevator down
        elif self.direction == 'down':
            self.floor -= 1


class Passenger(object):
    """An elevator Passenger."""

    def __init__(self, floor, destination):
        """Initialize a new passenger at a given floor and destination."""
        self.floor = floor
        self.destination = destination

    @property
    def direction(self):
        """Return the direction the passenger wants to go."""
        if self.destination > self.floor:
            return 'up'
        return 'down'

    def has_arrived(self, floor):
        """Return True if the passenger has arrived to its destination."""
        return floor == self.destination


class ElevatorController(object):
    """Central controller unit for elevator."""

    def __init__(self, elevators):
        """Initialize the controller."""
        self.elevators = elevators
        self.passengers = []

    def tick(self):
        """Rendering cycle for all the elevators."""
        for elevator in self.elevators:
            elevator.tick()

            for passenger in self.passengers:
                if passenger.floor == elevator.floor and \
                   elevator.direction in [passenger.direction, 'still']:
                    elevator.load(passenger)
                    self.passengers.remove(passenger)

    @property
    def score(self):
        """Return the sum of points each elevators collected."""
        return sum(e.points for e in self.elevators)

    def call(self, passenger):
        """
        Someone called an elevator.

        Elevator methods:
        elevator.floor: The floor where the elevator is
        elevator.destinations: an array containing the list of destinations
                               for the elevator
        elevator.direction: Can either be 'up', 'down' or 'still'
        elevator.add_destination(int): Add a new destination to the
                                       destination queue.
        elevator.distance(int): return the distance from the elevator
                                from a given floor
        elevator.load(Passenger): Load a passenger.
        """
        self.passengers.append(passenger)
        self.elevators[0].add_destination(passenger.destination)


elevator_controller = ElevatorController([Elevator('A'), Elevator('B')])

requests = [
    (3, 34), (28, 75), (90, 86), (10, 13), (27, 37), (98, 53), (38, 65),
    (80, 39), (5, 38), (52, 15), (99, 85), (18, 76), (81, 71), (88, 3),
    (78, 96), (34, 77), (99, 46), (85, 57), (65, 26), (97, 35), (88, 26),
    (48, 30), (44, 28), (35, 14), (48, 89), (3, 2), (96, 13), (80, 13),
    (2, 29), (55, 33), (17, 50), (38, 37), (95, 89), (80, 4), (49, 97),
    (98, 66), (40, 71), (59, 27), (32, 35), (84, 62), (35, 88), (70, 32),
    (56, 19), (63, 52), (23, 73), (22, 51), (62, 41), (82, 84), (26, 91),
    (64, 34), (56, 37), (49, 8), (76, 96), (77, 38), (78, 29), (47, 84),
    (79, 58), (43, 61), (20, 34), (28, 78), (8, 53), (87, 13), (98, 95),
    (36, 41), (100, 50), (96, 49), (44, 61), (40, 33), (28, 83), (18, 85),
    (46, 69), (2, 85), (77, 13), (96, 83), (49, 16), (64, 31), (50, 62),
    (68, 79), (63, 61), (55, 5), (1, 29), (64, 16), (75, 56), (57, 75),
    (16, 51), (23, 92), (60, 33), (18, 0), (2, 23), (30, 33), (93, 75),
    (23, 22), (15, 80), (20, 64), (79, 88), (8, 50), (67, 28), (100, 35),
    (13, 20), (87, 23)
]

for i in range(500):
    elevator_controller.tick()
    if i % 4 == 0 and requests:
        passenger = Passenger(*requests.pop())
        elevator_controller.call(passenger)

print 'score:', elevator_controller.score