class Queue(object):
def __init__(self):
"""
initialize your data structure here.
"""
self.queue = []
def push(self, x):
"""
:type x: int
:rtype: nothing
"""
self.queue.append(x)
def pop(self):
"""
:rtype: nothing
"""
ele = self.queue[0]
del self.queue[0]
return ele
def peek(self):
"""
:rtype: int
"""
ele = self.queue[0]
return ele
def empty(self):
"""
:rtype: bool
"""
return len(self.queue) == 0
https://leetcode.com/problems/implement-queue-using-stacks/#/description
Implement the following operations of a queue using stacks.
Notes:
push to top
, peek/pop from top
, size
, and is empty
operations are valid.