Capital One Interviews

My selection process for the SDE role at Capital One included two Online Assessments and one Technical Round, after which I was rejected.

Online Assessment 1 was a challenging 120-minute round with three DSA questions: one on connected components of a graph, another on bit manipulation, and a third on dynamic programming.

Online Assessment 2 was a unique 45-minute round. It featured one coding question, which was the classic Weighted Job Scheduling problem solvable with dynamic programming and binary search. Following that, there was a system design section. I was asked to design the backend system for a threading feature in a chat application like Slack or Microsoft Teams, allowing users to reply directly to messages without cluttering the main feed. This involved questions on non-functional features, data models, relationships, and API design.

The Technical Round, lasting 70-80 minutes, was entirely based on my performance in Online Assessment 2. For the DSA question, I had to explain my chosen approach, discuss alternatives, justify my conclusions, present test cases, and consider edge cases, which I believe I handled well, progressing from brute-force to an optimized DP solution. For the system design part, I first explained the feature's build flow, then discussed non-functional aspects and their importance. I also drew an ER model for the databases, addressed optimization questions, and wrote code for API calls.

I was rejected after this round. My main learning from this experience, particularly regarding system design, was the need to know more alternative methods for database durability beyond replicas, write-ahead logs, and backups. I also felt less confident in my ER model design and made a minor error in optimizing API calls. Despite not making it, I gained insight into the subsequent Managerial and HR rounds, which involve resume review and culture fit assessments.