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Singly Linked List vs Doubly Linked List: The Untold Story Every Programmer/QA Should Know
Have you ever wondered why in data structures, we don’t stop at a Singly Linked List (SLL) and go one step further to a Doubly Linked List (DLL)?
It’s like choosing between a simple bicycle (SLL) and a powerful motorbike (DLL). Both will get you from point A to B, but one has more gears, more flexibility, and yes… more fuel consumption (memory).
Let’s walk through this story. I’ll explain not with tables, but in a narrative that makes the differences crystal clear — so that next time you face an interview or design decision, you’ll know exactly which to pick.
A Quick Story to Set the Scene
Imagine you’re building a playlist app.
- With a Singly Linked List, you can only go forward. If you want to replay the previous song, sorry — you’ll have to start from the beginning and traverse again.
- With a Doubly Linked List, you can move both forward and backward. Want to replay that last track? Easy.
This simple story already tells you the core difference. Now let’s dive into the deeper, detailed differences that matter in real-world coding.
