Oracle SDE-1 — 4 Rounds, Offered

Timeline

• Applied: July 2026 (referral from college batchmate)
• Recruiter call: 3 days after referral
• All 4 rounds: Completed within 1 week
• Offer: 10 days from first round

Background

• 3 YOE, currently at a mid-size product company
• Full-stack (Java + React)
• No competitive programming background, mostly LeetCode prep for 2 months

Round 1 — Coding (45 min)

Questions:

1. Max profit from single buy-sell — Classic Kadane's variant. O(n) time, O(1) space. Straightforward.
2. Run-length encoding — Compress consecutive characters. Easy implementation, interviewer wanted clean code and edge cases (single char, empty string, all same chars).

Vibe: Relaxed. Interviewer was friendly, gave me time to think. Asked follow-ups about space complexity.

Round 2 — Coding + Puzzle (45 min)

Questions:

1. Bottom view of binary tree — BFS with horizontal distance tracking using a HashMap. Discussed why BFS is preferred over DFS for this problem.
2. Gold/Silver/Mix bag puzzle — Three bags wrongly labeled. Pick one item from one bag to correctly label all three. Solved it after 2 minutes of thinking out loud.

Discussion: Why Java's TreeMap vs HashMap for horizontal distance. Time complexity of BFS.

Round 3 — System Design Lite (45 min)

Not a full-blown system design round (expected for SDE-1 level).

Question: Design a URL shortener.

Covered:

• Hash function selection
• Collision handling
• Database schema (SQL vs NoSQL trade-offs)
• Caching layer with TTL
• Read-heavy vs write-heavy optimization

Interviewer pushed on: "What happens at 10M URLs? 100M?" Discussed horizontal scaling and consistent hashing.

Round 4 — Hiring Manager (30 min)

Behavioral focused:

• Why Oracle?
• Tell me about a challenging bug you fixed recently
• How do you handle code reviews when you disagree with feedback?
• What's your ideal engineering culture?

Straightforward conversation. HM was testing for culture fit and communication skills.

Tips for SDE-1 at Oracle

1. Coding rounds are medium difficulty — solid LeetCode medium practice is sufficient
2. They value clear communication over speed. Talk through your approach.
3. Know your fundamentals deeply — HashMaps, Trees, BFS/DFS, basic complexity analysis
4. The puzzle question is common in Oracle interviews — prepare a few classic logic puzzles
5. System design at SDE-1 is about demonstrating awareness, not expertise