[LeetCode] 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

设计停车系统。

请你给一个停车场设计一个停车系统。停车场总共有三种不同大小的车位：大，中和小，每种尺寸分别有固定数目的车位。

请你实现 ParkingSystem 类：

ParkingSystem(int big, int medium, int small) 初始化 ParkingSystem 类，三个参数分别对应每种停车位的数目。
bool addCar(int carType) 检查是否有 carType 对应的停车位。 carType 有三种类型：大，中，小，分别用数字 1， 2 和 3 表示。一辆车只能停在  carType 对应尺寸的停车位中。如果没有空车位，请返回 false ，否则将该车停入车位并返回 true 。


来源：力扣（LeetCode）
链接：https://leetcode-cn.com/problems/design-parking-system
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这是一道设计题。思路是用三个变量分别追踪三种size的停车位到底还剩几个，如果被用完了就只能return false了。

时间O(n)

空间O(1) - 只有三个变量

Java实现

 1 class ParkingSystem {
 2     int _big;
 3     int _medium;
 4     int _small;
 5 
 6     public ParkingSystem(int big, int medium, int small) {
 7         _big = big;
 8         _medium = medium;
 9         _small = small;
10     }
11 
12     public boolean addCar(int carType) {
13         if (carType == 1 && _big > 0) {
14             _big--;
15             return true;
16         }
17         if (carType == 2 && _medium > 0) {
18             _medium--;
19             return true;
20         }
21         if (carType == 3 && _small > 0) {
22             _small--;
23             return true;
24         }
25         return false;
26     }
27 }
28 
29 /**
30  * Your ParkingSystem object will be instantiated and called as such:
31  * ParkingSystem obj = new ParkingSystem(big, medium, small);
32  * boolean param_1 = obj.addCar(carType);
33  */

 

LeetCode 题目总结

posted @ 2021-03-20 05:23  CNoodle  阅读(365)  评论(0)    收藏  举报