Round 1

Design a DS to insert, delete, search and get a random integer. All operations should be O(1). Follow up - how would you handle these operations in a multi threaded environment?

Questions on design patterns, SQL v NoSQL, single and composite indices data structure.

Round 2

HLD: Design Cowin for vaccination management and tracking. Update vaccination center information, search and book slots, auth etc.

Verdict

Rejected.