I got this problem in my onsite round today, I still feel follow up is on tougher side of interview.
Want to know what is level of this follow up problem according to you considering google?

I solved initial problem easily with code but couldn't optimise follow up.

Initial Question:
https://leetcode.com/problems/the-earliest-moment-when-everyone-become-friends/description/

Follow-up:
Two types of logs

Add Friend - A and B become friends
Remove Friend - If A and B are friends, unfriend them
Two people can be connected and disconnected multiple times.

Given this, find the earliest timestamp when all of them become friends