Traversal and Printing a Linked List in DSA Python - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to move to the next node in the linked list.

DSA Python

current = head
while current is not None:
    print(current.data)
    current = current[1]

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

A.prev

B.head

C.data

D.next

Attempts:

3 left

💡 Hint

Common Mistakes

Using .prev instead of .next moves backward, which is incorrect for forward traversal.

Using .data instead of .next tries to assign data to current, causing errors.

The next attribute points to the next node in the linked list. Moving current to current.next traverses the list.

2fill in blank

medium

Complete the code to start traversal from the first node of the linked list.

DSA Python

def print_list(head):
    current = [1]
    while current is not None:
        print(current.data)
        current = current.next

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

Ahead

Bhead.next

CNone

Dcurrent

Attempts:

3 left

💡 Hint

Common Mistakes

Starting from head.next skips the first node.

Starting from None means no traversal happens.

Traversal starts from the head node, so current should be set to head.

3fill in blank

hard

Fix the error in the loop condition to correctly traverse the linked list.

DSA Python

current = head
while current[1]None:
    print(current.data)
    current = current.next

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

A!=

B=

Cis

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' assigns instead of compares, causing errors.

Using '==' checks equality but loop should continue while not None.

Using 'is' would check if current is None, preventing traversal.

The loop should continue while current is not None, so the condition must be current != None.

4fill in blank

hard

Fill both blanks to create a dictionary of node data and their positions in the linked list.

DSA Python

positions = {}
index = 0
current = head
while current is not None:
    positions[[1]] = index
    current = [2]
    index += 1

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

Acurrent.data

Bcurrent.next

Cindex

Dhead

Attempts:

3 left

💡 Hint

Common Mistakes

Using index as key stores position as key, which is incorrect here.

Using head instead of current.next causes infinite loop.

Use current.data as the key to store the index. Move to the next node with current.next.

5fill in blank

hard

Fill all three blanks to create a list of node data values from the linked list.

DSA Python

def list_values(head):
    values = []
    current = [1]
    while current is not None:
        values.[2](current.[3])
        current = current.next
    return values

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

Ahead

Bappend

Cdata

Dpop

Attempts:

3 left

💡 Hint

Common Mistakes

Using pop removes items instead of adding.

Starting from current instead of head causes error if current undefined.

Start from head, add each node's data to values using append.