Design Parking Lot

1// Enums
2enum VehicleType {
3    CAR, TRUCK, MOTORCYCLE, VAN
4}
5
6enum ParkingSpotType {
7    COMPACT, LARGE, HANDICAPPED, MOTORCYCLE
8}
9
10// Vehicle class
11abstract class Vehicle {
12    protected String licensePlate;
13    protected VehicleType type;
14    
15    public Vehicle(String licensePlate, VehicleType type) {
16        this.licensePlate = licensePlate;
17        this.type = type;
18    }
19    
20    public VehicleType getType() {
21        return type;
22    }
23}
24
25class Car extends Vehicle {
26    public Car(String licensePlate) {
27        super(licensePlate, VehicleType.CAR);
28    }
29}
30
31class Motorcycle extends Vehicle {
32    public Motorcycle(String licensePlate) {
33        super(licensePlate, VehicleType.MOTORCYCLE);
34    }
35}
36
37// Parking Spot
38class ParkingSpot {
39    private int id;
40    private ParkingSpotType type;
41    private Vehicle vehicle;
42    private boolean isOccupied;
43    
44    public ParkingSpot(int id, ParkingSpotType type) {
45        this.id = id;
46        this.type = type;
47        this.isOccupied = false;
48    }
49    
50    public boolean canFitVehicle(Vehicle vehicle) {
51        if (isOccupied) return false;
52        
53        switch (vehicle.getType()) {
54            case MOTORCYCLE:
55                return true; // Can fit in any spot
56            case CAR:
57                return type == ParkingSpotType.COMPACT || 
58                       type == ParkingSpotType.LARGE;
59            case TRUCK:
60                return type == ParkingSpotType.LARGE;
61            default:
62                return false;
63        }
64    }
65    
66    public void parkVehicle(Vehicle vehicle) {
67        this.vehicle = vehicle;
68        this.isOccupied = true;
69    }
70    
71    public void removeVehicle() {
72        this.vehicle = null;
73        this.isOccupied = false;
74    }
75}
76
77// Parking Floor
78class ParkingFloor {
79    private int floorNumber;
80    private List<ParkingSpot> spots;
81    
82    public ParkingFloor(int floorNumber) {
83        this.floorNumber = floorNumber;
84        this.spots = new ArrayList<>();
85    }
86    
87    public void addSpot(ParkingSpot spot) {
88        spots.add(spot);
89    }
90    
91    public ParkingSpot findAvailableSpot(Vehicle vehicle) {
92        for (ParkingSpot spot : spots) {
93            if (spot.canFitVehicle(vehicle)) {
94                return spot;
95            }
96        }
97        return null;
98    }
99}
100
101// Parking Lot (Singleton)
102class ParkingLot {
103    private static ParkingLot instance;
104    private List<ParkingFloor> floors;
105    private Map<String, ParkingSpot> vehicleSpotMap;
106    
107    private ParkingLot() {
108        floors = new ArrayList<>();
109        vehicleSpotMap = new HashMap<>();
110    }
111    
112    public static synchronized ParkingLot getInstance() {
113        if (instance == null) {
114            instance = new ParkingLot();
115        }
116        return instance;
117    }
118    
119    public void addFloor(ParkingFloor floor) {
120        floors.add(floor);
121    }
122    
123    public boolean parkVehicle(Vehicle vehicle) {
124        for (ParkingFloor floor : floors) {
125            ParkingSpot spot = floor.findAvailableSpot(vehicle);
126            if (spot != null) {
127                spot.parkVehicle(vehicle);
128                vehicleSpotMap.put(vehicle.licensePlate, spot);
129                return true;
130            }
131        }
132        return false; // No available spot
133    }
134    
135    public boolean unparkVehicle(String licensePlate) {
136        ParkingSpot spot = vehicleSpotMap.get(licensePlate);
137        if (spot != null) {
138            spot.removeVehicle();
139            vehicleSpotMap.remove(licensePlate);
140            return true;
141        }
142        return false;
143    }
144}