Python Data Structures and Algorithms

Enqueue operation

Elements are added to a Queue object via the enqueue method. The elements in this case are the nodes:

    def enqueue(self, data):         new_node = Node(data, None, None)         if self.head is None:             self.head = new_node             self.tail = self.head         else:             new_node.prev = self.tail             self.tail.next = new_node             self.tail = new_node         self.count += 1 

The enqueue method code is the same code already explained in the append operation of the doubly linked list. It creates a node from the data passed to it and appends it to the tail of the queue, or points both self.head and self.tail to the newly created node if the queue is empty. The total count of elements in the queue is increased by the line self.count += 1.