实现一个MyQueue类，该类用两个栈来实现一个队列。
示例：
MyQueue queue = new MyQueue();
queue.push(1);
queue.push(2);
queue.peek(); // 返回 1
queue.pop(); // 返回 1
queue.empty(); // 返回 false示例代码1：
class MyQueue(object):
def __init__(self):
"""
Initialize your data structure here.
"""
self.queue = []
def push(self, x):
"""
Push element x to the back of queue.
:type x: int
:rtype: None
"""
self.queue.append(x)
def pop(self):
"""
Removes the element from in front of queue and returns that element.
:rtype: int
"""
return self.queue.pop(0)
def peek(self):
"""
Get the front element.
:rtype: int
"""
return self.queue[0]
def empty(self):
"""
Returns whether the queue is empty.
:rtype: bool
"""
if len(self.queue) == 0:
return True
else:
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()示例代码2：
class MyQueue(object):
def __init__(self):
"""
Initialize your data structure here.
"""
self.stack1 = []
self.stack2 = []
def push(self, x):
"""
Push element x to the back of queue.
:type x: int
:rtype: None
"""
self.stack1.append(x)
def pop(self):
"""
Removes the element from in front of queue and returns that element.
:rtype: int
"""
if len(self.stack2) == 0:
while self.stack1:
self.stack2.append(self.stack1.pop())
return self.stack2.pop()
def peek(self):
"""
Get the front element.
:rtype: int
"""
if len(self.stack2) == 0:
while self.stack1:
self.stack2.append(self.stack1.pop())
return self.stack2[-1]
def empty(self):
"""
Returns whether the queue is empty.
:rtype: bool
"""
return len(self.stack1) == 0 and len(self.stack2) == 0
# 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()
