Implement the following operations of a stack using queues.
Example:
MyStack stack = new MyStack(); stack.push(1); stack.push(2); stack.top(); // returns 2 stack.pop(); // returns 2 stack.empty(); // returns false
class MyStack: def __init__(self): """ Initialize your data structure here. """ from collections import deque self.queue = deque() def push(self, x: int) -> None: """ Push element x onto stack. """ self.queue.append(x) for i in range(len(self.queue) - 1): 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 # Your MyStack object will be instantiated and called as such: # obj = MyStack() # obj.push(x) # param_2 = obj.pop() # param_3 = obj.top() # param_4 = obj.empty()
[LC] 225. Implement Stack using Queues
原文：https://www.cnblogs.com/xuanlu/p/11781045.html