1603. Design Parking System

Problem

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

Solution (Java)

class ParkingSystem {
    private final int[] slots = new int[3];

    public ParkingSystem(int big, int medium, int small) {
        slots[0] = big;
        slots[1] = medium;
        slots[2] = small;
    }

    public boolean addCar(int carType) {
        if (carType == 1) {
            if (slots[0] > 0) {
                slots[0]--;
                return true;
            } else {
                return false;
            }
        } else if (carType == 2) {
            if (slots[1] > 0) {
                slots[1]--;
                return true;
            } else {
                return false;
            }
        } else {
            if (slots[2] > 0) {
                slots[2]--;
                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);
 */

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).