Started with intro, I felt like the interviewer was nervous and rambling as they just came off a meeting
Asked CS fundamentals:
Virtual Memory - perfect
Process vs Thread - pefrect
Database normilization - mentioned the write read tradeoff and deduplication, they didn't seem satisfied
How to implement a hashmap from scratch - Caught off graud, couldn't remember, said something but it was wrong, this shouldn't have happened

Coding -
Nest list weight sum 2 - 4 followups
two pass DFS
Single pass BFS
Single pass DFS (said ignore the call stack space and optimise space) -> told to store level sum in a has map
Single pass DFS with constant space -> using formula (maxdepth + 1 ) * unweighted_sum - normal_weighted_sum -> needed a hint for this one

Coding and dry run was near perfect in one go

Thoughts:
Could have asked two questions instead of one, ignoring the stack space dosen't make sense and stack overflow is a possibility, honestly didn't like the followups, meh

Update: Got the mail for onsite