What are the types of Linked Lists? (Singly, Doubly, Circular)

Difficulty: 3/10

linked list variants, pointer manipulation, memory layout

Types of Linked Lists

The three common forms are Singly Linked List, Doubly Linked List, and Circular Linked List. They differ primarily in how nodes reference neighboring nodes and whether the final node terminates at null or connects back into the list.

javascript

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Singly Linked List: each node contains a next reference.
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Doubly Linked List: each node contains both next and previous references.
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Circular Linked List: the last node points back to a node in the list, commonly the head.
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Doubly linked lists simplify backward traversal and deletion when a node reference is available.
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Circular lists are useful for round-robin scheduling and cyclic iteration.

Scenario Questions

0-2 years experience

1If you need to implement a basic playlist where you can add songs to the end and iterate forward, which linked list type would you choose and why?
2How would you insert a new node after a given node in a singly linked list? Walk me through the pointer changes.

2-5 years experience

1We have a feature that requires fast removal of nodes from both ends of a list. Which linked list variant would you pick and what trade‑offs does it bring?

Follow-up Questions

What is the memory overhead difference between singly and doubly linked lists?
When might making a list circular be advantageous or problematic?
How would you test edge cases like an empty list or a single‑node circular list?