Delete Node by Value in DSA Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does 'Delete Node by Value' mean in a linked list?

It means finding the first node that contains a specific value and removing it from the linked list, adjusting links so the list stays connected.

beginner

Why do we need to handle the head node differently when deleting by value?

Because the head node is the start of the list, if it contains the value to delete, we must update the head pointer to the next node to keep the list valid.

beginner

What happens if the value to delete is not found in the linked list?

No nodes are removed, and the linked list remains unchanged.

intermediate

In the deletion process, why do we keep track of the previous node?

Because to remove a node, we need to change the previous node's next pointer to skip the node being deleted.

intermediate

What is the time complexity of deleting a node by value in a singly linked list?

O(n), where n is the number of nodes, because we may need to check each node until we find the value or reach the end.

What should you do if the node to delete is the head node in a singly linked list?

A Do nothing

B Delete the entire list

C Update the head pointer to the next node

D Swap the head with the last node

The head pointer must be updated to the next node to remove the current head.

If the value to delete is not found, what happens to the linked list?

A It remains unchanged

B The head node is deleted

C The last node is deleted

D It becomes empty

No deletion occurs if the value is not found, so the list stays the same.

Why do we need to keep track of the previous node when deleting a node by value?

A To update the previous node's next pointer

B To print the list

C To find the last node

D To reverse the list

We update the previous node's next pointer to skip the node being deleted.

What is the worst-case time complexity of deleting a node by value in a singly linked list?

A O(1)

B O(n)

C O(log n)

D O(n^2)

We may need to traverse the entire list to find the node, so it is O(n).

Which of these is NOT a step in deleting a node by value?

A Handle the case when the node is the head

B Update the previous node's next pointer

C Find the node with the value

D Create a new node with the value

Creating a new node is not part of deletion; deletion removes nodes.

Explain step-by-step how to delete a node by value in a singly linked list.

Think about how to keep the list connected after removing the node.

What special cases must you consider when deleting a node by value in a linked list?

Consider the start of the list and empty list scenarios.