text: Insertion Sort for Doubly Linked List | Node of a doubly linked list ; function to create and return a new node of a doubly linked list ; allocate node ; put in the data ; function to insert a new node in sorted way in a sorted doubly linked list ; if list is empty ; if the node is to be inserted at the beginning of the doubly linked list ; locate the node after which the new node is to be inserted ; Make the appropriate links ; if the new node is not inserted at the end of the list ; function to sort a doubly linked list using insertion sort ; Initialize ' sorted ' - a sorted doubly linked list ; Traverse the given doubly linked list and insert every node to 'sorted   ; Store next for next iteration ; removing all the links so as to create ' current ' as a new node for insertion ; insert current in ' sorted ' doubly linked list ; Update current ; Update head_ref to point to sorted doubly linked list ; function to print the doubly linked list ; function to insert a node at the beginning of the doubly linked list ; allocate node ; put in the data ; Make next of new node as head and previous as None ; change prev of head node to new node ; move the head to point to the new node ; Driver Code ; start with the empty doubly linked list ; insert the following data
code: class Node : NEW_LINE INDENT def __init__ ( self , data ) : NEW_LINE INDENT self . data = data NEW_LINE self . prev = None NEW_LINE self . next = None NEW_LINE DEDENT DEDENT def getNode ( data ) : NEW_LINE INDENT newNode = Node ( 0 ) NEW_LINE newNode . data = data NEW_LINE newNode . prev = newNode . next = None NEW_LINE return newNode NEW_LINE DEDENT def sortedInsert ( head_ref , newNode ) : NEW_LINE INDENT current = None NEW_LINE if ( head_ref == None ) : NEW_LINE INDENT head_ref = newNode NEW_LINE DEDENT elif ( ( head_ref ) . data >= newNode . data ) : NEW_LINE INDENT newNode . next = head_ref NEW_LINE newNode . next . prev = newNode NEW_LINE head_ref = newNode NEW_LINE DEDENT else : NEW_LINE INDENT current = head_ref NEW_LINE while ( current . next != None and current . next . data < newNode . data ) : NEW_LINE INDENT current = current . next NEW_LINE DEDENT newNode . next = current . next NEW_LINE if ( current . next != None ) : NEW_LINE INDENT newNode . next . prev = newNode NEW_LINE DEDENT current . next = newNode NEW_LINE newNode . prev = current NEW_LINE DEDENT return head_ref ; NEW_LINE DEDENT def insertionSort ( head_ref ) : NEW_LINE INDENT sorted = None NEW_LINE current = head_ref NEW_LINE while ( current != None ) : NEW_LINE INDENT next = current . next NEW_LINE current . prev = current . next = None NEW_LINE sorted = sortedInsert ( sorted , current ) NEW_LINE current = next NEW_LINE DEDENT head_ref = sorted NEW_LINE return head_ref NEW_LINE DEDENT def printList ( head ) : NEW_LINE INDENT while ( head != None ) : NEW_LINE INDENT print ( head . data , end = " ▁ " ) NEW_LINE head = head . next NEW_LINE DEDENT DEDENT def push ( head_ref , new_data ) : NEW_LINE INDENT new_node = Node ( 0 ) NEW_LINE new_node . data = new_data NEW_LINE new_node . next = ( head_ref ) NEW_LINE new_node . prev = None NEW_LINE if ( ( head_ref ) != None ) : NEW_LINE INDENT ( head_ref ) . prev = new_node NEW_LINE DEDENT ( head_ref ) = new_node NEW_LINE return head_ref NEW_LINE DEDENT if __name__ == " _ _ main _ _ " : NEW_LINE INDENT head = None NEW_LINE head = push ( head , 9 ) NEW_LINE head = push ( head , 3 ) NEW_LINE head = push ( head , 5 ) NEW_LINE head = push ( head , 10 ) NEW_LINE head = push ( head , 12 ) NEW_LINE head = push ( head , 8 ) NEW_LINE print ( " Doubly ▁ Linked ▁ List ▁ Before ▁ Sorting " ) NEW_LINE printList ( head ) NEW_LINE head = insertionSort ( head ) NEW_LINE print ( " Doubly Linked List After Sorting " ) NEW_LINE printList ( head ) NEW_LINE DEDENT