# 1603. Design Parking System

## Description

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
[[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

## Solutions

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.

• class ParkingSystem {
private int[] cnt;

public ParkingSystem(int big, int medium, int small) {
cnt = new int[] {0, big, medium, small};
}

if (cnt[carType] == 0) {
return false;
}
--cnt[carType];
return true;
}
}

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

• class ParkingSystem {
public:
vector<int> cnt;

ParkingSystem(int big, int medium, int small) {
cnt = {0, big, medium, small};
}

if (cnt[carType] == 0) return false;
--cnt[carType];
return true;
}
};

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

• class ParkingSystem:
def __init__(self, big: int, medium: int, small: int):
self.cnt = [0, big, medium, small]

def addCar(self, carType: int) -> bool:
if self.cnt[carType] == 0:
return False
self.cnt[carType] -= 1
return True

# Your ParkingSystem object will be instantiated and called as such:
# obj = ParkingSystem(big, medium, small)


• type ParkingSystem struct {
cnt []int
}

func Constructor(big int, medium int, small int) ParkingSystem {
return ParkingSystem{[]int{0, big, medium, small} }
}

func (this *ParkingSystem) AddCar(carType int) bool {
if this.cnt[carType] == 0 {
return false
}
this.cnt[carType]--
return true
}

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

• class ParkingSystem {
private count: [number, number, number];

constructor(big: number, medium: number, small: number) {
this.count = [big, medium, small];
}

if (this.count[carType - 1] === 0) {
return false;
}
this.count[carType - 1]--;
return true;
}
}

/**
* Your ParkingSystem object will be instantiated and called as such:
* var obj = new ParkingSystem(big, medium, small)
*/


• public class ParkingSystem {

private List<int> cnt;

public ParkingSystem(int big, int medium, int small) {
cnt = new List<int>() {0 , big, medium, small};
}

if (cnt[carType] == 0) {
return false;
}
--cnt[carType];
return true;
}
}

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


• struct ParkingSystem {
count: [i32; 3],
}

/**
* &self means the method takes an immutable reference.
* If you need a mutable reference, change it to &mut self instead.
*/
impl ParkingSystem {
fn new(big: i32, medium: i32, small: i32) -> Self {
Self {
count: [big, medium, small],
}
}

fn add_car(&mut self, car_type: i32) -> bool {
let i = (car_type - 1) as usize;
if self.count[i] == 0 {
return false;
}
self.count[i] -= 1;
true
}
}/**
* Your ParkingSystem object will be instantiated and called as such:
* let obj = ParkingSystem::new(big, medium, small);
* let ret_1: bool = obj.add_car(carType);
*/