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38 lines (32 loc) · 752 Bytes
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implementqueueusingstacks.py
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38 lines (32 loc) · 752 Bytes
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class Queue(object):
def __init__(self):
"""
initialize your data structure here.
"""
self.instack = []
self.outstack = []
def push(self, x):
"""
:type x: int
:rtype: nothing
"""
self.instack.append(x)
def pop(self):
"""
:rtype: nothing
"""
self.peek()
self.outstack.pop()
def peek(self):
"""
:rtype: int
"""
if not self.outstack:
while self.instack:
self.outstack.append(self.instack.pop())
return self.outstack[-1]
def empty(self):
"""
:rtype: bool
"""
return len(self.instack) + len(self.outstack) == 0