lintcode 40. 用栈实现队列

难度：中等

1. Description

40. 用栈实现队列

2. Solution

• python
  用两个栈，十分巧妙。

class MyQueue:
    
    def __init__(self):
        # do intialization if necessary
        self.stack1 = []
        self.stack2 = []
    
    def adjust(self):
        if len(self.stack2)==0:
            while len(self.stack1)>0:
                self.stack2.append(self.stack1.pop())

    """
    @param: element: An integer
    @return: nothing
    """
    def push(self, element):
        # write your code here
        self.stack1.append(element)

    """
    @return: An integer
    """
    def pop(self):
        # write your code here
        self.adjust()
        return self.stack2.pop()

    """
    @return: An integer
    """
    def top(self):
        # write your code here
        self.adjust()
        return self.stack2[-1]

3. Reference

1. https://www.lintcode.com/problem/implement-queue-by-two-stacks/?_from=ladder