Earliest Time a Friendship Network Is Fully Connected with Friend and Unfriend Events
Company: Google
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Onsite
Overview: Given an unsorted log of timestamped friend and unfriend events among n people, return the earliest time at which everyone is connected through chains of friendships, or -1 if that never happens. It tests connectivity reasoning when edges can be both added and removed, event ordering, and careful handling of groups that split apart again.