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Queue.py
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Queue.py
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# from queue import *
# q = Queue()
class Node:
def __init__(self, value=None, next=None, prev=None):
self.value = value
self.next = next
self.prev = prev
def __repr__(self):
return str(self.value)
class Queue:
def __init__(self):
self.back = None
self.front = None
def enqueue(self, elem):
# q.put(elem)
if(self.back == None): #q.empty()
self.front = Node(elem)
self.back = self.front
else:
n = self.back
self.back = Node(elem, n)
n.prev = self.back
def dequeue(self):
# q.get()
n = self.front
if n.prev != None:
self.front = self.front.prev
self.front.next = None
else:
self.front = None
self.back = self.front
return n
def peek(self):
return self.front
def __repr__(self):
p = self.back
s = ""
while p != None:
s += str(p)+"->"
p = p.next
return s