Delete Node at Specific Position in DSA Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the first step when deleting a node at a specific position in a singly linked list?

Check if the list is empty or if the position is valid (e.g., position is not negative and within the list length).

beginner

How do you delete the head node (position 0) in a singly linked list?

Make the head point to the next node, effectively removing the first node from the list.

intermediate

Why do we need to keep track of the previous node when deleting a node at a specific position (other than head)?

Because we need to update the previous node's next pointer to skip the node being deleted.

beginner

What happens if the position to delete is greater than the length of the linked list?

No deletion occurs because the position is invalid; the list remains unchanged.

intermediate

In a singly linked list, what is the time complexity of deleting a node at a specific position?

O(n), where n is the position index, because you may need to traverse the list to reach that position.

What should you do first before deleting a node at a specific position in a linked list?

A Create a new node

B Delete the head node directly

C Traverse the entire list twice

D Check if the position is valid and the list is not empty

Always check if the position is valid and the list is not empty before deletion.

How do you delete the node at position 0 in a singly linked list?

A Set head to head.next

B Set head to null

C Traverse to the last node

D Swap data with next node

Deleting the head means moving the head pointer to the next node.

When deleting a node at position > 0, what pointer must be updated?

A Previous node's next pointer

B Head pointer

C Tail pointer

D Current node's previous pointer

The previous node's next pointer must skip the deleted node.

What happens if the position to delete is outside the list length?

A List is reversed

B No deletion occurs

C First node is deleted

D Last node is deleted

Invalid positions do not cause deletion.

What is the time complexity to delete a node at position n in a singly linked list?

A O(1)

B O(log n)

C O(n)

D O(n^2)

Traversal to the position takes O(n) time.

Explain the steps to delete a node at a specific position in a singly linked list.

Think about how pointers change when removing a node.

Describe how deleting a node at position 0 differs from deleting at other positions in a singly linked list.

Focus on the role of the head pointer.