Insert at End 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'

Atail

Bhead

CNone

Ddata

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'head' or 'tail' instead of the data value.

Passing None instead of data.

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

2fill in blank

medium

Complete the code to check if the list is empty.

DSA Python

if [1] is None:

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

Ahead

Btail

Cnew_node

Ddata

Attempts:

3 left

💡 Hint

Common Mistakes

Checking new_node instead of head.

Checking tail instead of head.

If head is None, the list is empty.

3fill in blank

hard

Fix the error in the code to update the tail's next pointer.

DSA Python

tail.[1] = new_node

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

Anext

Bprev

Cdata

Dhead

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'prev' instead of 'next'.

Trying to assign to 'data' or 'head'.

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

4fill in blank

hard

Fill both blanks to update the new node's previous pointer and move the tail.

DSA Python

new_node.[1] = tail
 tail = [2]

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

Aprev

Bnew_node

Cnext

Dhead

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'next' instead of 'prev' for the new node.

Not updating tail to the new node.

The new node's prev points to the old tail, then tail moves to new_node.

5fill in blank

hard

Fill all three blanks to complete the insert_at_end function.

DSA Python

def insert_at_end(head, tail, data):
    new_node = Node([1])
    if head is None:
        head = new_node
        tail = new_node
    else:
        tail.[2] = new_node
        new_node.[3] = tail
        tail = new_node
    return head, tail

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

Adata

Bnext

Cprev

Dhead

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up next and prev pointers.

Not updating tail after insertion.

Passing wrong value to Node constructor.

We create new_node with data, link tail.next to new_node, new_node.prev to tail, then update tail.