How do you find the intersection node of two singly linked lists?
PICTURE THIS: HOW TO EXPLAIN IT
Simple meaning
Two pointers walk both lists and switch to the other head on null
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:
- 1Two pointers walk both
lists and switch to the other head on null
- 2they meet at the
intersection or both at null.
- 3Time is O(n+m) and
space is O(1).
- 4Length-aligning by skipping the
extra prefix of the longer list is the equivalent two-pass idea.
- 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
Two pointers walk both lists and switch to the other head on null they meet at the intersection or both at null.