239. Sliding Window Maximum

225. Implement Stack using Queues

  1. class MyStack:
  3.     def __init__(self):
  4.         self.queue = collections.deque()
  6.     def push(self, x: int) -> None:
  7.         n = len(self.queue)
  8.         self.queue.append(x)
  9.         for _ in range(n):
  10.             self.queue.append(self.queue.popleft())
  12.     def pop(self) -> int:
  13.         return self.queue.popleft()
  15.     def top(self) -> int:
  16.         return self.queue[0]
  18.     def empty(self) -> bool:
  19.         return not self.queue
  • 时间复杂度：push()为队列 - 图1，其余操作为队列 - 图2
  • 空间复杂度：队列 - 图3