Question

379. 电话目录管理系统

English Version

题目描述

设计一个电话目录管理系统，让它支持以下功能：

1. get: 分配给用户一个未被使用的电话号码，获取失败请返回 -1
2. check: 检查指定的电话号码是否被使用
3. release: 释放掉一个电话号码，使其能够重新被分配

 

示例：

// 初始化电话目录，包括 3 个电话号码：0，1 和 2。
PhoneDirectory directory = new PhoneDirectory(3);

// 可以返回任意未分配的号码，这里我们假设它返回 0。
directory.get();

// 假设，函数返回 1。
directory.get();

// 号码 2 未分配，所以返回为 true。
directory.check(2);

// 返回 2，分配后，只剩一个号码未被分配。
directory.get();

// 此时，号码 2 已经被分配，所以返回 false。
directory.check(2);

// 释放号码 2，将该号码变回未分配状态。
directory.release(2);

// 号码 2 现在是未分配状态，所以返回 true。
directory.check(2);

 

提示：

• 1 <= maxNumbers <= 10^4
• 0 <= number < maxNumbers
• 调用方法的总数处于区间 [0 - 20000] 之内

解法

方法一

class PhoneDirectory:
  def __init__(self, maxNumbers: int):
    """
    Initialize your data structure here
    @param maxNumbers - The maximum numbers that can be stored in the phone directory.
    """
    self.provided = [False] * maxNumbers

  def get(self) -> int:
    """
    Provide a number which is not assigned to anyone.
    @return - Return an available number. Return -1 if none is available.
    """
    for i in range(len(self.provided)):
      if not self.provided[i]:
        self.provided[i] = True
        return i
    return -1

  def check(self, number: int) -> bool:
    """
    Check if a number is available or not.
    """
    return not self.provided[number]

  def release(self, number: int) -> None:
    """
    Recycle or release a number.
    """
    self.provided[number] = False


# Your PhoneDirectory object will be instantiated and called as such:
# obj = PhoneDirectory(maxNumbers)
# param_1 = obj.get()
# param_2 = obj.check(number)
# obj.release(number)

class PhoneDirectory {

  private boolean[] provided;

  /**
     Initialize your data structure here
    @param maxNumbers - The maximum numbers that can be stored in the phone directory.
   */
  public PhoneDirectory(int maxNumbers) {
    provided = new boolean[maxNumbers];
  }

  /**
     Provide a number which is not assigned to anyone.
    @return - Return an available number. Return -1 if none is available.
   */
  public int get() {
    for (int i = 0; i < provided.length; ++i) {
      if (!provided[i]) {
        provided[i] = true;
        return i;
      }
    }
    return -1;
  }

  /** Check if a number is available or not. */
  public boolean check(int number) {
    return !provided[number];
  }

  /** Recycle or release a number. */
  public void release(int number) {
    provided[number] = false;
  }
}

/**
 * Your PhoneDirectory object will be instantiated and called as such:
 * PhoneDirectory obj = new PhoneDirectory(maxNumbers);
 * int param_1 = obj.get();
 * boolean param_2 = obj.check(number);
 * obj.release(number);
 */