Queue

class Node:

    def __init__(self,value):
        self.value = value
        self.next = None

class Queue:

    def __init__(self,value):
        new_node = Node(value)
        self.first = new_node
        self.last = new_node
        self.length = 1

    def print_queue(self):
        temp = self.first
        while temp is not None:
            print(temp.value)
            temp = temp.next

    def enqueue(self,value):
        new_node = Node(value)
        if self.first is None:
            self.first = new_node
            self.last = new_node
        else:
            self.last.next = new_node
            self.last = new_node
        self.length+=1

    def dequeue(self):
        if self.first is None:
            return None

        if self.length==1:
            self.first = None
            self.last = None
        else:
            temp = self.first
            self.first = self.first.next
            temp.next = None
        self.length-=1

        return temp