Delete a Node from Circular 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 circular linked list.

DSA Python

current = head
current = current[1]

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

A.prev

B.child

C.next

D.parent

Attempts:

3 left

💡 Hint

Common Mistakes

Using '.prev' instead of '.next' to move forward.

Using attributes that don't exist like '.child' or '.parent'.

In a circular linked list, each node points to the next node using the 'next' attribute.

2fill in blank

medium

Complete the code to check if the list has only one node.

DSA Python

if head[1] head.next:

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

A<

B!=

C>

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using '!=' which checks for inequality instead of equality.

Using comparison operators like '>' or '<' which are not valid for node references.

If head is equal to head.next, it means the list has only one node pointing to itself.

3fill in blank

hard

Fix the error in the code to correctly delete the head node from the circular linked list.

DSA Python

head.data = head.next.data
head.next = head[1]

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

A.prev

B.next.next

C.next

D.next.prev

Attempts:

3 left

💡 Hint

Common Mistakes

Linking head.next to head.next which causes no change.

Using '.prev' which is not relevant here.

Using '.next.prev' which is invalid in this context.

To delete the head node, copy data from the next node and link head.next to head.next.next to skip the deleted node.

4fill in blank

hard

Fill both blanks to correctly find the node before the one to delete and update links.

DSA Python

prev = head
while prev.next[1] != current:
    prev = prev.next
prev.next = current[2]

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

A.next

B.prev

C.next.next

D.next.prev

Attempts:

3 left

💡 Hint

Common Mistakes

Using '.prev' which is not used in singly linked circular lists.

Linking prev.next to current.prev which is invalid.

Incorrect loop condition causing infinite loops.

To find the node before current, move while prev.next != current. Then link prev.next to current.next to remove current.

5fill in blank

hard

Fill all three blanks to complete the function that deletes a node with given key from circular linked list.

DSA Python

def delete_node(head, key):
    if head is None:
        return None
    current = head
    prev = None
    while True:
        if current.data == [1]:
            if prev is not None:
                prev.next = current[2]
            else:
                head = current[3]
            return head
        prev = current
        current = current.next
        if current == head:
            break
    return head

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

Akey

B.next

Dhead.next

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names for key comparison.

Not updating head when deleting the head node.

Incorrectly linking nodes causing broken list.

Check if current.data equals key. If deleting non-head node, link prev.next to current.next. If deleting head, update head to head.next.