题目:
题解:
class MyStack:def __init__(self):"""Initialize your data structure here."""self.queue = collections.deque()def push(self, x: int) -> None:"""Push element x onto stack."""n = len(self.queue)self.queue.append(x)for _ in range(n):self.queue.append(self.queue.popleft())def pop(self) -> int:"""Removes the element on top of the stack and returns that element."""return self.queue.popleft()def top(self) -> int:"""Get the top element."""return self.queue[0]def empty(self) -> bool:"""Returns whether the stack is empty."""return not self.queue