1603. Design Parking System

Design a parking system for a parking lot. The parking lot has three kinds of parking spaces: big, medium, and small, with a fixed number of slots for each size.

Implement the ParkingSystem class:

• ParkingSystem(int big, int medium, int small) Initializes object of the ParkingSystem class. The number of slots for each parking space are given as part of the constructor.
• bool addCar(int carType) Checks whether there is a parking space of carType for the car that wants to get into the parking lot. carType can be of three kinds: big, medium, or small, which are represented by 1, 2, and 3 respectively. A car can only park in a parking space of its carType. If there is no space available, return false, else park the car in that size space and return true.

Example 1:

Input
["ParkingSystem", "addCar", "addCar", "addCar", "addCar"]
[[1, 1, 0], [1], [2], [3], [1]]
Output
[null, true, true, false, false]

Explanation
ParkingSystem parkingSystem = new ParkingSystem(1, 1, 0);
parkingSystem.addCar(1); // return true because there is 1 available slot for a big car
parkingSystem.addCar(2); // return true because there is 1 available slot for a medium car
parkingSystem.addCar(3); // return false because there is no available slot for a small car
parkingSystem.addCar(1); // return false because there is no available slot for a big car. It is already occupied.

Constraints:

• 0 <= big, medium, small <= 1000
• carType is 1, 2, or 3
• At most 1000 calls will be made to addCar

class ParkingSystem {
    Map<Integer, Integer> map;
    public ParkingSystem(int big, int medium, int small) {
        map = new HashMap();
        map.put(1, big);
        map.put(2, medium);
        map.put(3, small);
    }
    
    public boolean addCar(int carType) {
        if(map.get(carType) > 0) {
            map.put(carType, map.get(carType) - 1);
            return true;
        }
        else return false;
    }
}

/**
 * Your ParkingSystem object will be instantiated and called as such:
 * ParkingSystem obj = new ParkingSystem(big, medium, small);
 * boolean param_1 = obj.addCar(carType);
 */

hashmap

class ParkingSystem {
    int[] arr;
    public ParkingSystem(int big, int medium, int small) {
        arr = new int[]{big, medium, small};
    }
    
    public boolean addCar(int carType) {
        if(arr[carType - 1] > 0) {
            arr[carType - 1]--;
            return true;
        }
        else return false;
    }
}