How do you reverse a singly linked list iteratively?
PICTURE THIS: STACK VS QUEUE
Simple meaning
Walk with prev, curr, and next: save curr.next, point curr.next to prev, then advance prev and curr.
WHY — Linked List instead of guessing?
Why interviewers care about Linked List:
question about Linked List.
trade-offs, and what you would actually do on a DSA project - not buzzwords.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1Walk with prev, curr,
and next: save curr.next, point curr.next to prev, then advance prev and curr.
- 2One O(n) pass and
O(1) extra space, returning prev as the new head.
- 3Recursion is O(n) stack
space, so prefer iterative unless they ask for the recursive form.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
Walk with prev, curr, and next: save curr.next, point curr.next to prev, then advance prev and curr. One O(n) pass and O(1) extra space, returning prev as the new head.