---
title: leetcode-225
date: 2020-03-23 23:35:05
tags:
categories: leetcode
---

### 225. 用队列实现栈

[题目](https://leetcode-cn.com/problems/implement-stack-using-queues/)



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注意栈是 FILO(First In Last Out)，Python 的 list 是 FIFO(First In First Out)。

```python
class MyStack:

  def __init__(self):
    """
    Initialize your data structure here.
    """
    self.data = []


  def push(self, x: int) -> None:
    """
    Push element x onto stack.
    """
    self.data.append(x)
    return


  def pop(self) -> int:
    """
    Removes the element on top of the stack and returns that element.
    """
    return self.data.pop(-1)


  def top(self) -> int:
    """
    Get the top element.
    """
    return self.data[-1]


  def empty(self) -> bool:
    """
    Returns whether the stack is empty.
    """
    return not bool(self.data)



# 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()

#24 ms	13.5 MB
```