Formatted question description: https://leetcode.ca/all/1603.html

1603. Design Parking System (Easy)

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

Related Topics:
Design

Solution 1.

Maintain an array of length 3 that stores the number of slots with three car types.

For the constructor, initialize the array with big, medium and small.

For method addCar, check whether the number of slots of the given carType is greater than 0. If so, decrease the number of slots of the given carType by 1 and return true. Otherwise, return false.

Cpp

// OJ: https://leetcode.com/problems/design-parking-system/

// Time: O(1)
// Space: O(1)
class ParkingSystem {
    array<int, 3> space;
public:
    ParkingSystem(int big, int medium, int small) {
        space = { big, medium, small };
    }
    bool addCar(int carType) {
        return space[carType - 1]-- > 0;
    }
};

Java

class ParkingSystem {
    int[] slots;

    public ParkingSystem(int big, int medium, int small) {
        slots = new int[3];
        slots[0] = big;
        slots[1] = medium;
        slots[2] = small;
    }
    
    public boolean addCar(int carType) {
        carType--;
        if (slots[carType] > 0) {
            slots[carType]--;
            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);
 */

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