基础题队列933、225、622、641

 1 class RecentCounter:
 2 
 3     def __init__(self):
 4         self.q = collections.deque()
 5 
 6     def ping(self, t: int) -> int:
 7         self.q.append(t)
 8 
 9         while self.q[0] < t - 3000:
10             self.q.popleft()
11 
12         return len(self.q)
13 
14 
15 
16 # Your RecentCounter object will be instantiated and called as such:
17 # obj = RecentCounter()
18 # param_1 = obj.ping(t)