Doubly Linked List — DSA Technical Interview Questions & Answers

Doubly Linked List

Doubly Linked List

  • Doubly Linked List is a DSA topic. In plain words you use it for a ticket queue node in a counter. Don’t start with a slogan — start with that picture.
  • Smallest example: head → next → …. Type it, run it, and say what you see. If you can do that from memory, you know Doubly Linked List.
  • From the example next to this theory: Doubly Linked List — a linked list chains nodes with next pointers instead of contiguous indexes.
  • Trap: losing the next pointer on delete. Fix that before you talk about advanced DSA.
  • Viva: what is Doubly Linked List? Then show head → next → …. Then name the trap.

Technical Interview Tip: What is Doubly Linked List? Show this: head → next → …. Trap: losing the next pointer on delete.

Code Examples for Doubly Linked List

Doubly Linked List — working example

class Node:
    def __init__(self, val, next=None):
        self.val = val
        self.next = next

head = Node(1, Node(2, Node(3)))
cur = head
while cur:
    print(cur.val, end=" -> " if cur.next else "\n")
    cur = cur.next

Doubly Linked List — a linked list chains nodes with next pointers instead of contiguous indexes.

How to Explain Doubly Linked List to an Interviewer

What is Doubly Linked List?

Used for a ticket queue node a counter Not just the heading

Give one small example of Doubly Linked List.

head → next → … Doubly Linked List — a linked list chains nodes with next pointers instead of contiguous indexes

What mistake do beginners make with Doubly Linked List?

losing the next pointer on delete Show the fix

Where do you use Doubly Linked List?

a counter a ticket queue node