Build a Constant-Time Snapshot Set Iterator
Company: Databricks
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: hard
Interview Round: Onsite
Overview: Design a mutable integer set whose iterators preserve insertion-order snapshots without copying the live set when they are created. Meet constant-time creation and update targets, support independent iterators and remove-then-readd behavior, and explain skipped history and safe reclamation.