Design a Parking Lot [CCIB]

Data Structure Design:

Solution:
Cracking the coding interview Book - Page 323 - 6th edition

OO Design:
1. https://xmruibi.gitbooks.io/interview-preparation-notes/content/OOD/DesignExamples/ParkingLot.html

The parking lot has multiple slots.

The parking lot can park motorcycles, cars, and buses.

The parking lot has small slots, compact slots, and large slots.

A motorcycle can park in any slot.

A car can park in either a single compact slot or a single large slot.

A bus can park only in a single large slot.

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abstract class Vehicle {       }

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class Motorcycle extends Vehicle{       }

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class Car extends Vehicle {       }

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class Bus extends Vehicle {       }

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abstract class Slot {           private boolean isOccupied;        private int slotNumber;                 Slot(int slotNumber) {         isOccupied = false;         this.slotNumber = slotNumber;        }           boolean isOccupied() {         return isOccupied;     }           int getSlotNumber() {         return slotNumber;     }           void park() {         isOccupied = true;     }           void unPark() {        isOccupied = false;     }           @Override     public boolean equals(Object o) {         return (((Slot) o).slotNumber == this.slotNumber);     }     @Override     public int hashCode() {         int hash = 5;         hash = 53 * hash + this.slotNumber;         return hash;     }      }

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class SmallSlot extends Slot {           SmallSlot(int slotNumber){         super(slotNumber);     } }

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class CompactSlot extends Slot {           CompactSlot(int slotNumber) {         super(slotNumber);     } }

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class LargeSlot extends Slot {     LargeSlot(int slotNumber)  {         super(slotNumber);     } }

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public class ParkingLot {     private static final int NUMBER_OF_SMALL_SLOTS = 10;     private static final int NUMBER_OF_COMPACT_SLOTS = 10;     private static final int NUMBER_OF_LARGE_SLOTS = 10;     public Map<Long, Slot> occupiedSlots;     private List<Slot> smallSlots;     private List<Slot> compactSlots;     private List<Slot> largeSlots;     public ParkingLot() {         smallSlots = new ArrayList<>(NUMBER_OF_SMALL_SLOTS);         compactSlots = new ArrayList<>(NUMBER_OF_COMPACT_SLOTS);         largeSlots = new ArrayList<>(NUMBER_OF_LARGE_SLOTS);         createSlots();         occupiedSlots = new HashMap<>();     }     private void createSlots() {         for (int i = 1; i <= NUMBER_OF_SMALL_SLOTS; i++) {             smallSlots.add(new SmallSlot(i));         }         for (int i = 1; i <= NUMBER_OF_COMPACT_SLOTS; i++) {             compactSlots.add(new CompactSlot(i));         }         for (int i = 1; i <= NUMBER_OF_LARGE_SLOTS; i++) {             largeSlots.add(new LargeSlot(i));         }     }     public long park(Vehicle vehicle) {         Slot slot;         long uniqueToken = -1;         if (vehicle instanceof Motorcycle) {             if ((slot = getFirstEmptySlot(smallSlots)) != null) {                 uniqueToken = parkHelper(slot, vehicle);             } else if ((slot = getFirstEmptySlot(compactSlots)) != null) {                 uniqueToken = parkHelper(slot, vehicle);             } else if ((slot = getFirstEmptySlot(largeSlots)) != null) {                 uniqueToken = parkHelper(slot, vehicle);             }         } else if (vehicle instanceof Car) {             if ((slot = getFirstEmptySlot(compactSlots)) != null) {                 uniqueToken = parkHelper(slot, vehicle);             } else if ((slot = getFirstEmptySlot(largeSlots)) != null) {                 uniqueToken = parkHelper(slot, vehicle);             }         } else {             if ((slot = getFirstEmptySlot(largeSlots)) != null) {                 uniqueToken = parkHelper(slot, vehicle);             }         }         return uniqueToken;     }     public void unPark(long uniqueToken) {         occupiedSlots.get(uniqueToken).unPark();         occupiedSlots.remove(uniqueToken);     }     private Slot getFirstEmptySlot(List<Slot> slots) {         Iterator<Slot> slotIterator = slots.iterator();         boolean isSlotFound = false;         Slot emptySlot = null;         while (slotIterator.hasNext() && !isSlotFound) {             emptySlot = slotIterator.next();             if (!emptySlot.isOccupied()) {                 isSlotFound = true;             }         }         return emptySlot;     }     private long parkHelper(Slot slot, Vehicle vehicle) {         slot.park();         long uniqueToken = vehicle.hashCode() * 43;         occupiedSlots.put(uniqueToken, slot);         return uniqueToken;     } }

2. http://www.coderanch.com/t/628047/patterns/Parking-Lot-Design

Extra:
http://massivetechinterview.blogspot.in/2015/07/cc150v5-84-design-parking-lot.html

Valet Parking
http://www.careercup.com/question?id=5750856565653504