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

Problem Summary #

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 the ParkingSystem class. The three parameters correspond to the number of parking spaces of each type.
• bool addCar(int carType) Checks whether there is a parking space corresponding to carType. carType has three types: big, medium, and small, represented by the numbers 1, 2, and 3 respectively. A car can only park in a parking space of the size corresponding to  carType. If there is no available parking space, return false; otherwise, park the car in the space and return true.

Solution Ideas #

• Easy problem. Use 3 variables to represent big, medium, and small parking spaces respectively. addCar() only needs to check whether these 3 variables still have available spaces.

Code #

package leetcode

type ParkingSystem struct {
	Big    int
	Medium int
	Small  int
}

func Constructor(big int, medium int, small int) ParkingSystem {
	return ParkingSystem{
		Big:    big,
		Medium: medium,
		Small:  small,
	}
}

func (this *ParkingSystem) AddCar(carType int) bool {
	switch carType {
	case 1:
		{
			if this.Big > 0 {
				this.Big--
				return true
			}
			return false
		}
	case 2:
		{
			if this.Medium > 0 {
				this.Medium--
				return true
			}
			return false
		}
	case 3:
		{
			if this.Small > 0 {
				this.Small--
				return true
			}
			return false
		}
	}
	return false
}

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