双端队列：求解《933. 最近的请求次数》

var RecentCounter = function() {
  this.q = []
};

RecentCounter.prototype.ping = function(t) {
  this.q.push(t)
  while (this.q[0] < t - 3000) this.q.shift()
  return this.q.length
};

class RecentCounter {
  q: number[] = []
  constructor() {
  }

  ping(t: number): number {
    this.q.push(t)
    while (this.q[0] < t - 3000) this.q.shift()
    return this.q.length
  }
}

type RecentCounter struct {
  q []int
}

func Constructor() RecentCounter {
  return RecentCounter{q: []int{}}
}

func (this *RecentCounter) Ping(t int) int {
  this.q = append(this.q, t)
  for this.q[0] < t - 3000 {
    this.q = this.q[1:]
  }
  return len(this.q)
}

class RecentCounter {
  private $q;
  function __construct() {
    $this->q = [];
  }
  function ping($t) {
    $this->q []= $t;
    while ($this->q[0] < $t - 3000) array_shift($this->q);
    return count($this->q);
  }
}

class RecentCounter(object):
    def __init__(self):
      self.q = deque()

    def ping(self, t):
      self.q.append(t)
      while self.q[0] < t - 3000: self.q.popleft()
      return len(self.q)

class RecentCounter {
  private Deque<Integer> q;
  public RecentCounter() {
    q = new ArrayDeque<>();
  }

  public int ping(int t) {
    q.offerLast(t);
    while (q.getFirst() < t - 3000) q.pollFirst();
    return q.size();
  }
}

class RecentCounter {
  private Deque<Integer> q;
  public RecentCounter() {
    q = new ArrayDeque<>();
  }

  public int ping(int t) {
    q.offer(t);
    while (q.peek() < t - 3000) q.poll();
    return q.size();
  }
}