Insert at Beginning of Doubly Linked List in DSA Python - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a new node with the given data.

DSA Python

new_node = Node([1])

Drag options to blanks, or click blank then click option'

ANone

Bdata

Chead

Dprev

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'head' instead of 'data' when creating the new node.

Passing None instead of the data value.

We create a new node by passing the data value to the Node constructor.

2fill in blank

medium

Complete the code to link the new node's next pointer to the current head.

DSA Python

new_node.next = [1]

Drag options to blanks, or click blank then click option'

Ahead

Bnew_node

CNone

Dprev

Attempts:

3 left

💡 Hint

Common Mistakes

Setting new_node.next to None instead of head.

Setting new_node.next to new_node itself.

The new node's next pointer should point to the current head node.

3fill in blank

hard

Fix the error in updating the previous pointer of the old head node.

DSA Python

if head is not None:
    head.[1] = new_node

Drag options to blanks, or click blank then click option'

Adata

Bnext

Cprev

Dhead

Attempts:

3 left

💡 Hint

Common Mistakes

Updating head.next instead of head.prev.

Assigning head.data instead of a pointer.

The previous pointer of the old head should point back to the new node.

4fill in blank

hard

Fill both blanks to update the head pointer and set the new node's previous pointer.

DSA Python

head = [1]
head.[2] = None

Drag options to blanks, or click blank then click option'

Anew_node

Bprev

Cnext

Dhead

Attempts:

3 left

💡 Hint

Common Mistakes

Setting head to old head instead of new node.

Setting head.next to None instead of head.prev.

The head pointer is updated to the new node, and its previous pointer is set to None.

5fill in blank

hard

Fill all three blanks to complete the insert_at_beginning function for a doubly linked list.

DSA Python

def insert_at_beginning(head, data):
    new_node = Node([1])
    new_node.next = [2]
    if head is not None:
        head.prev = new_node
    head = new_node
    head.prev = [3]
    return head

Drag options to blanks, or click blank then click option'

Adata

Bhead

CNone

Dnew_node

Attempts:

3 left

💡 Hint

Common Mistakes

Not updating the old head's prev pointer.

Setting new_node.prev incorrectly.

Returning the old head instead of the new head.

We create a new node with data, link its next to the old head, update old head's prev, set head to new node, and set new head's prev to None.