Assignment 1

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Kernel: Python 3 (Anaconda)

import random import string import copy

class Building(): def init(self, num_of_floor, num_of_passenger): self.num_of_floor = num_of_floor self.num_of_passenger = num_of_passenger self.passengers = [] #list of all passengers self.random_passengers() #generate random passengers

def random_passengers(self):
    for i in range(self.num_of_passenger):
        p = Passenger(random.randrange(self.num_of_floor), random.randrange(self.num_of_floor)) #generates an origin and a destination

        # make sure the origin and destination is different
        while p.origin == p.destination:
            p.destination = random.randrange(self.num_of_floor)

        self.passengers.append(p) #add random passenger to building

###########################################################################

class Passenger(): def init(self, origin, destination): self.name = "".join(random.choice(string.ascii_uppercase)) + "".join(random.choice(string.ascii_lowercase) for _ in range(random.randrange(2, 8))) # a random name for the passenger for console display self.origin = origin self.destination = destination self.deliver = 0 # marker of if the passenger is delivered, 0=undelivered 1=delivered self.cost = 0 # the cost to deliver the passenger

def compute_cost(self, movement):
    self.cost = movement - abs(self.origin - self.destination)
    print("Drop off", self.name, "at floor", self.destination, "with cost", self.cost)

###########################################################################

class Elevator(): def init(self, capacity, position=0, direction=1): self.capacity = capacity # max allowed people in the elevator self.position = position # current position of the elevator, defalut to 0 self.movement = 0 # count the total movement of the elevator, used to calculate cost function self.direction = direction # last moving direction of the elevator, 0=down 1=up, default to 1 self.carrying = [] # a collection of passengers currently inside the elevator

def move(self):
    # move one floor following the given direction
    if self.direction == 1:
        self.position += 1
    else:
        self.position -= 1

    self.movement += 1   # increment the total movement by 1 as the elevator has moved one more step

def drop_passenger(self):
    # go through all passengers on the elevator to check if they reached their destination
    dropped = []
    for key, object in enumerate(self.carrying):
        if object.destination == self.position: #mark if passenger is at destination floor
            dropped.append(key) #add passenger to be dropped
            object.compute_cost(self.movement)
    
    if dropped: #removed dropped passengers from elevator
        self.carrying = [p for ind, p in enumerate(self.carrying) if ind not in dropped]


def reverse(self):
    if self.direction == 1:
        self.direction = 0
    else:
        self.direction = 1

###########################################################################

Strategy 1 has 3 principles:

1. The elevator will always favour its current moving direction.

2. Unless reached its capacity, the elevator will take all encountered passengers that are going in the same direction.

3. The elevator will reverse its current moving direction if:

1. There is no passenger currently inside the elevator.

2. There is no undelivered passenger in the elevator's current direction

def strategy_1(b, e): #inputs a building and an elevator awaiting = copy.copy(b.passengers) #list of passengers in the building e.carrying = [] #reset elevator while len(awaiting) > 0 or len(e.carrying) > 0: #while there are people to be picked up or people to deliver print("The elevator is at", e.position, "carrying", len(e.carrying), "passengers")

    # at each floor, first check if there is a passenger to drop
    e.drop_passenger()

    # if the elevator still has capacity, check if there is passenger to carry
    if len(awaiting) > 0 and len(e.carrying) < e.capacity:
        DEL = []
        for key, object in enumerate(awaiting): #loop through all waiting passengers in the building
            if e.position == object.origin:
                if ((object.destination - object.origin) > 0) == e.direction:   # if the elevator is going in the direction the passenger wants to go
                    e.carrying.append(object) #pick up passenger
                    DEL.append(key) # add passenger to be removed from elevator calls
                    print("Picking up", object.name, "at floor", e.position)
                    if len(e.carrying) == e.capacity:
                        break   # when capacity is reached, stop checking if there are passengers to pick up (break for loop)
        if DEL:
            awaiting = [p for ind, p in enumerate(awaiting) if ind not in DEL] #remove dropped passengers from awaiting list

    # decide if to reverse
    if len(e.carrying) == 0: #if the elevator isn't carrying any passengers
        reverse = 1 #reverse direction unless
        for object in awaiting: #there are passengers to pick up in the current direction
            if ((object.origin - e.position) > 0) == e.direction:
                reverse = 0
                break
        if reverse == 1:
            e.reverse()

    # if there's a passenger waiting in the same direction, move one floor; if not, keep the position and re-evaluate
    if len(e.carrying) > 0 or reverse == 0:
        e.move()

    # break in case of infinite loop
    if e.movement > 10000: break

# calculate the total cost
total_cost = 0
for _, object in enumerate(b.passengers):
    print(object.name, "going from floor", object.origin, "to floor", object.destination,"have a cost of", object.cost)
    total_cost += object.cost
print("The total cost is", total_cost)

###########################################################################

#Strategy 2:

Elevator goes all the way up and then down and opens door at every floor

def strategy_2(b, e): #inputs a building and an elevator awaiting = copy.copy(b.passengers) #list of passengers in the building e.carrying = [] #reset elevator while len(awaiting) > 0 or len(e.carrying) > 0: #while there are people to be picked up or people to deliver print("The elevator is at", e.position, "carrying", len(e.carrying), "passengers")

    # at each floor, first check if there is a passenger to drop
    e.drop_passenger()
    
    # if the elevator still has capacity, check if there is passenger to carry
    if len(awaiting) > 0 and len(e.carrying) < e.capacity:
        DEL = []
        for key, object in enumerate(awaiting): #loop through all waiting passengers in the building
            print(e.position, object.name, object.origin)
            if e.position == object.origin:
                e.carrying.append(object) #pick up passenger
                DEL.append(key) # add passenger to be removed from elevator calls
                print("Picking up", object.name, "at floor", e.position)
                if len(e.carrying) == e.capacity:
                    break   # when capacity is reached, stop checking if there are passengers to pick up (break for loop)
        if DEL:
            awaiting = [p for ind, p in enumerate(awaiting) if ind not in DEL] #remove dropped passengers from awaiting list

    # decide if to reverse
    if e.position == b.num_of_floor: #if at the top, go down
        e.direction = 0
    elif e.position == 0: #if on ground floor, go back up
        e.direction = 1
    
    #move elevator in up or down direction
    e.move()

    # break in case of infinite loop
    if e.movement > 100: break

# calculate the total cost
total_cost = 0
for _, object in enumerate(b.passengers):
    print(object.name, "going from floor", object.origin, "to floor", object.destination,"have a cost of", object.cost)
    total_cost += object.cost
print("The total cost is", total_cost)

###########################################################################

In [0]:

In [1]:

building_1 = Building(50, 25)
elevator_1 = Elevator(10)

strategy_1(copy.copy(building_1), copy.copy(elevator_1))
strategy_2(copy.copy(building_1), copy.copy(elevator_1))

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-1-f2f634e0e7a0> in <module>()
----> 1 building_1 = Building(50, 25)
      2 elevator_1 = Elevator(10)
      3 
      4 strategy_1(copy.copy(building_1), copy.copy(elevator_1))
NameError: name 'Building' is not defined

In [0]:

In [65]:

strategy_2(copy.copy(building_1), copy.copy(elevator_1))

The elevator is at 0 carrying 0 passengers
The elevator is at 1 carrying 0 passengers
Picking up Cqfdsmil at floor 1
The elevator is at 2 carrying 1 passengers
The elevator is at 3 carrying 1 passengers
The elevator is at 4 carrying 1 passengers
The elevator is at 5 carrying 1 passengers
The elevator is at 6 carrying 1 passengers
The elevator is at 7 carrying 1 passengers
Picking up Hjxfqz at floor 7
The elevator is at 8 carrying 2 passengers
Drop off Hjxfqz at floor 8 with cost 7
The elevator is at 9 carrying 1 passengers
Picking up Ahnqujya at floor 9
The elevator is at 10 carrying 2 passengers
The elevator is at 9 carrying 2 passengers
The elevator is at 8 carrying 2 passengers
The elevator is at 7 carrying 2 passengers
The elevator is at 6 carrying 2 passengers
The elevator is at 5 carrying 2 passengers
The elevator is at 4 carrying 2 passengers
The elevator is at 3 carrying 2 passengers
The elevator is at 2 carrying 2 passengers
Drop off Ahnqujya at floor 2 with cost 11
The elevator is at 1 carrying 1 passengers
The elevator is at 0 carrying 1 passengers
Drop off Cqfdsmil at floor 0 with cost 19
Cqfdsmil going from floor 1 to floor 0 have a cost of 19
Ahnqujya going from floor 9 to floor 2 have a cost of 11
Hjxfqz going from floor 7 to floor 8 have a cost of 7
The total cost is 37

In [0]: