class MyStack:
def __init__(self):
"""
Initialize your data structure here.
"""
self.queue1 = deque()
self.queue2 = deque()
def push(self, x: int) -> None:
"""
Push element x onto stack.
"""
self.queue2.append(x)
while self.queue1:
self.queue2.append(self.queue1.popleft())
self.queue2,self.queue1=self.queue1,self.queue2
def pop(self) -> int:
"""
Removes the element on top of the stack and returns that element.
"""
if not self.queue1:
return 0
return self.queue1.popleft()
def top(self) -> int:
"""
Get the top element.
"""
if not self.queue1:
return 0
return self.queue1[0]
def empty(self) -> bool:
"""
Returns whether the stack is empty.
"""
return len(self.queue1)==0
LEETCODE 225. 用队列实现栈
2024-05-04 16:54:02 32 阅读