It was a first telephonic interview and I was being asked a coding interview after an initial introduction.

It was question 160. Intersection of two linkedlist.

Not sure if interviewer was expecting me to solve 2 problems in this telephonic interview. It took me a second to come up with O(n) time and O(n) space solution.

I was being asked to solve in O(1) space. Tried hard and finally figured the answer.