Obj Flashcards
1
Q
Design Parking Lot (Full)
A
class Vehicle:
def \_\_init\_\_(self, spot_size):
self._spot_size = spot_size
def get_spot_size(self):
return self._spot_size
class Driver:
def \_\_init\_\_(self, id, vehicle):
self._id = id
self._vehicle = vehicle
self._payment_due = 0
def get_vehicle(self):
return self._vehicle
def get_id(self):
return self._id
def charge(self, amount):
self._payment_due += amount
class Car(Vehicle):
def \_\_init\_\_(self):
super().\_\_init\_\_(1)
class Limo(Vehicle):
def \_\_init\_\_(self):
super().\_\_init\_\_(2)
class SemiTruck(Vehicle):
def \_\_init\_\_(self):
super().\_\_init\_\_(3)
class ParkingFloor:
def \_\_init\_\_(self, spot_count):
self._spots = [0]*spot_count
self._vehicle_map = {}
def park_vehicle(self, vehicle):
size = vehicle.get_spot_size()
l, r = 0, 0
while r < len(self._spots):
if self._spots[r] != 0:
l = r + 1
if r - l + 1 == size:
# we found enough spots, park the vehicle
for k in range(l, r+1):
self._spots[k] = 1
self._vehicle_map[vehicle] = [l, r]
return True
r += 1
return False
def remove_vehicle(self, vehicle):
start, end = self._vehicle_map[vehicle]
for i in range(start, end + 1):
self._spots[i] = 0
del self._vehicle_map[vehicle]
def get_parking_spots(self):
return self._spots
def get_vehicle_spots(self, vehicle):
return self._vehicle_map.get(vehicle)
class ParkingGarage:
def \_\_init\_\_(self, floor_count, spots_per_floor):
self._parking_floors = [ParkingFloor(spots_per_floor) for _ in range(floor_count)]
def park_vehicle(self, vehicle):
for floor in self._parking_floors:
if floor.park_vehicle(vehicle):
return True
return False
def remove_vehicle(self, vehicle):
for floor in self._parking_floors:
if floor.get_vehicle_spots(vehicle):
floor.remove_vehicle(vehicle)
return True
return False
import datetime
import math
class ParkingSystem:
def \_\_init\_\_(self, parkingGarage, hourlyRate):
self._parkingGarage = parkingGarage
self._hourlyRate = hourlyRate
self._timeParked = {} # map driverId to time that they parked
def park_vehicle(self, driver):
currentHour = datetime.datetime.now().hour
isParked = self._parkingGarage.park_vehicle(driver.get_vehicle())
if isParked:
self._timeParked[driver.get_id()] = currentHour
return isParked
def remove_vehicle(self, driver):
if driver.get_id() not in self._timeParked:
return False
currentHour = datetime.datetime.now().hour
timeParked = math.ceil(currentHour - self._timeParked[driver.get_id()])
driver.charge(timeParked * self._hourlyRate)
del self._timeParked[driver.get_id()]
return self._parkingGarage.remove_vehicle(driver.get_vehicle())
parkingGarage = ParkingGarage(3, 2)
parkingSystem = ParkingSystem(parkingGarage, 5)
driver1 = Driver(1, Car())
driver2 = Driver(2, Limo())
driver3 = Driver(3, SemiTruck())
print(parkingSystem.park_vehicle(driver1)) # true
print(parkingSystem.park_vehicle(driver2)) # true
print(parkingSystem.park_vehicle(driver3)) # false
print(parkingSystem.remove_vehicle(driver1)) # true
print(parkingSystem.remove_vehicle(driver2)) # true
print(parkingSystem.remove_vehicle(driver3)) # false
2
Q
Vehicle Class
A
class Vehicle:
def \_\_init\_\_(self, spot_size):
self._spot_size = spot_size
def get_spot_size(self):
return self._spot_size
3
Q
Driver Class
A
class Driver:
def \_\_init\_\_(self, id, vehicle):
self._id = id
self._vehicle = vehicle
self._payment_due = 0
def get_vehicle(self):
return self._vehicle
def get_id(self):
return self._id
def charge(self, amount):
self._payment_due += amount
4
Q
Cars, Limos, Semitrucks
A
class Car(Vehicle):
def \_\_init\_\_(self):
super().\_\_init\_\_(1)
class Limo(Vehicle):
def \_\_init\_\_(self):
super().\_\_init\_\_(2)
class SemiTruck(Vehicle):
def \_\_init\_\_(self):
super().\_\_init\_\_(3)
5
Q
Parking Floor Class
A
class ParkingFloor:
def \_\_init\_\_(self, spot_count):
self._spots = [0] * spot_count
self._vehicle_map = {}
def park_vehicle(self, vehicle):
size = vehicle.get_spot_size()
l, r = 0, 0
while r < len(self._spots):
if self._spots[r] != 0:
l = r + 1
if r - l + 1 == size:
# we found enough spots, park the vehicle
for k in range(l, r+1):
self._spots[k] = 1
self._vehicle_map[vehicle] = [l, r]
return True
r += 1
return False
def remove_vehicle(self, vehicle):
start, end = self._vehicle_map[vehicle]
for i in range(start, end + 1):
self._spots[i] = 0
del self._vehicle_map[vehicle]
def get_parking_spots(self):
return self._spots
def get_vehicle_spots(self, vehicle):
return self._vehicle_map.get(vehicle)
6
Q
Parking Garage Class
A
class ParkingGarage:
def \_\_init\_\_(self, floor_count, spots_per_floor):
self._parking_floors = [ParkingFloor(spots_per_floor) for _ in range(floor_count)]
def park_vehicle(self, vehicle):
for floor in self._parking_floors:
if floor.park_vehicle(vehicle):
return True
return False
def remove_vehicle(self, vehicle):
for floor in self._parking_floors:
if floor.get_vehicle_spots(vehicle):
floor.remove_vehicle(vehicle)
return True
return False
