Oracle || SDE3 || Interview Experience

I had a 4-round interview process. The interview focused mainly on DSA, HLD/System Design, and behavioral questions.

Round 1 — Technical

The round started with a DSA question:

• Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit
  https://leetcode.com/problems/longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit/

After DSA, the interviewer asked a few system design/backend concepts:

• How does pagination work?
• How would you implement pagination at the API and database level?
• How does OAuth 2.0 work?
• How would you handle data loss in a distributed system?

Round 2 — System Design

This round was primarily focused on HLD.

I was asked to design a temporary email service where:

• Users can generate a temporary email address.
• The email address remains active for 5 hours.
• During those 5 hours, the user can receive emails on that address.
• After 5 hours, the temporary email and its associated data should be deleted/expired.
• The interviewer also asked how I would handle the large volume of emails/data generated by the system and how the cleanup process would work.

The discussion covered storage, expiration, cleanup, scalability, and handling a large amount of data.

Round 3 — HM Round

The round started with a few behavioral questions.

After that, I was asked a DSA question based on prescription records.

Given records:

patientId, doctorId, drugName, date

The task was to find patient + drug pairs where the same drug was prescribed by different doctors within 30 days.

Additional conditions:

• Input is sorted by date.
• A pair should be printed only once.
• Output should be: patientId drugName.

Example:

P1 D1 Atorvastatin 2025-01-10
P1 D2 Atorvastatin 2025-02-05
P2 D3 Metformin    2025-03-01
P2 D4 Metformin    2025-03-25

Output:

P1 Atorvastatin
P2 Metformin

After the DSA question, I was asked to design an HLD for a movie/concert booking system.

Round 4 — Bar Raiser

The final round was a Bar Raiser round.

It started with some behavioral questions, followed by an HLD question which I don't remember exactly.

After that, I was asked a backtracking-based DSA question.

Overall, the process had a good mix of DSA, HLD, backend fundamentals, and behavioral questions.