Question

1603. 设计停车系统

English Version

题目描述

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 。

 

示例 1：

输入：
["ParkingSystem", "addCar", "addCar", "addCar", "addCar"]
[[1, 1, 0], [1], [2], [3], [1]]
输出：
[null, true, true, false, false]

解释：
ParkingSystem parkingSystem = new ParkingSystem(1, 1, 0);
parkingSystem.addCar(1); // 返回 true ，因为有 1 个空的大车位
parkingSystem.addCar(2); // 返回 true ，因为有 1 个空的中车位
parkingSystem.addCar(3); // 返回 false ，因为没有空的小车位
parkingSystem.addCar(1); // 返回 false ，因为没有空的大车位，唯一一个大车位已经被占据了

 

提示：

• 0 <= big, medium, small <= 1000
• carType 取值为 1， 2 或 3
• 最多会调用 addCar 函数 1000 次

解法

方法一：模拟

为每种车维护一个计数器，初始值为车位的数目。此后，每来一辆车，就将对应类型的计数器减 1。当计数器为 0 时，说明车位已满。

时间复杂度 $O(1)$，空间复杂度 $O(1)$。

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)
# param_1 = obj.addCar(carType)

class ParkingSystem {
  private int[] cnt;

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

  public boolean addCar(int carType) {
    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);
 * boolean param_1 = obj.addCar(carType);
 */

class ParkingSystem {
public:
  vector<int> cnt;

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

  bool addCar(int carType) {
    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);
 * bool param_1 = obj->addCar(carType);
 */

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);
 * param_1 := obj.AddCar(carType);
 */

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

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

  addCar(carType: number): boolean {
    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)
 * var param_1 = obj.addCar(carType)
 */

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);
 */

public class ParkingSystem {

  private List<int> cnt;

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

  public bool AddCar(int carType) {
    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);
 * bool param_1 = obj.AddCar(carType);
 */

typedef struct {
  int* count;
} ParkingSystem;

ParkingSystem* parkingSystemCreate(int big, int medium, int small) {
  ParkingSystem* res = malloc(sizeof(ParkingSystem));
  res->count = malloc(sizeof(int) * 3);
  res->count[0] = big;
  res->count[1] = medium;
  res->count[2] = small;
  return res;
}

bool parkingSystemAddCar(ParkingSystem* obj, int carType) {
  int i = carType - 1;
  if (!obj->count[i]) {
    return 0;
  }
  obj->count[i]--;
  return 1;
}

void parkingSystemFree(ParkingSystem* obj) {
  free(obj);
}

/**
 * Your ParkingSystem struct will be instantiated and called as such:
 * ParkingSystem* obj = parkingSystemCreate(big, medium, small);
 * bool param_1 = parkingSystemAddCar(obj, carType);

 * parkingSystemFree(obj);
*/