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queue_ll.py
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queue_ll.py
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class Node:
def __init__(self, data, next=None):
self.data = data
self.next = next
def __str__(self):
return str(self.data)
__repr__ = __str__
class Queue:
def __init__(self):
self.head = None
self.tail = None
def enqueue(self, data):
if self.tail is None:
self.head = Node(data)
self.tail = self.head
else:
self.tail.next = Node(data)
self.tail = self.tail.next
def dequeue(self):
if self.is_empty():
return None
else:
res = self.head
self.head = self.head.next
return str(res)
def is_empty(self):
return self.head is None
if __name__ == "__main__":
queue = Queue()
queue.enqueue(1)
queue.enqueue(2)
print(queue.dequeue())
queue.enqueue(3)
print(queue.dequeue())
queue.enqueue(4)
queue.enqueue(5)
print(queue.dequeue())
print(queue.dequeue())
print(queue.dequeue())
print(queue.is_empty())
print(queue.dequeue())