每日一道Leetcode - 面试题 03.04. 化栈为队 【栈】

class MyQueue:

    def __init__(self):
        """
        Initialize your data structure here.
        """
        self.stack1 = []
        self.stack2 = []


    def push(self, x: int) -> None:
        """
        Push element x to the back of queue.
        """
        self.stack1.append(x)


    def pop(self) -> int:
        """
        Removes the element from in front of queue and returns that element.
        """
        if self.stack2:
            return self.stack2.pop()
        while self.stack1:
            self.stack2.append(self.stack1.pop())
        return self.stack2.pop()


    def peek(self) -> int:
        """
        Get the front element.
        """
        if self.stack2:
            return self.stack2[-1]
        while self.stack1:
            self.stack2.append(self.stack1.pop())
        return self.stack2[-1]


    def empty(self) -> bool:
        """
        Returns whether the queue is empty.
        """
        if not self.stack1 and not self.stack2:
            return True
        return False



# Your MyQueue object will be instantiated and called as such:
# obj = MyQueue()
# obj.push(x)
# param_2 = obj.pop()
# param_3 = obj.peek()
# param_4 = obj.empty()

标签：面试题,return,化栈,self,pop,为队,obj,stack2,stack1
来源： https://blog.csdn.net/weixin_41041275/article/details/113788501