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Amazon·Software Engineer·Online Assessment (OA)·Junior

JuniorPending
Jun 2026

Summary

Took the Amazon OA recently, two questions total: one DSA and one AI backend. Got through the DSA fine but the backend question was rough, only 1 out of 6 test cases passed, so now I'm just waiting and hoping for the best.

Questions Asked (2)

Q1

A data structures and algorithms problem included in the Amazon online assessment.

Algorithms & Data Structures
Author's notes

This one went okay.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the problem constraints and edge cases, then discuss a brute-force solution before optimizing with an efficient data structure or algorithm. Walk through the time and space complexity trade-offs, and finally implement and test the solution with examples.

Pro tip: Amazon values customer obsession and ownership, so explicitly connect your solution to scalability and real-world impact, such as handling large inputs efficiently. Also, proactively test your code with edge cases to demonstrate thoroughness.

1. Understand and Clarify

Ask clarifying questions to confirm input/output formats, constraints, and edge cases. Restate the problem in your own words to ensure alignment.

2. Explore Approaches

Discuss a brute-force solution first, then propose optimizations using appropriate data structures or algorithms. Compare trade-offs in time and space complexity.

3. Plan and Implement

Outline your chosen approach step-by-step, then write clean, modular code. Use meaningful variable names and handle edge cases explicitly.

4. Test and Validate

Walk through your code with normal and edge-case inputs, including empty inputs, large values, and duplicates. Debug and fix any issues.

5. Analyze and Optimize

State the final time and space complexity, and discuss potential further optimizations or alternative solutions if needed.

Key Points to Mention

  • Time and space complexity analysis (Big O notation)
  • Edge cases such as empty input, single element, duplicates, and large inputs
  • Choice of data structures (e.g., hash maps, heaps, trees) and why they are optimal
  • Trade-offs between different approaches (e.g., sorting vs. hashing)
  • Scalability and real-world applicability, aligning with Amazon's leadership principles
  • Code readability and modularity for maintainability

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.

Q2

An AI backend implementation question included in the Amazon online assessment.

System DesignTechnical Trade-offs
Author's notes

This is where things fell apart.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the requirements and constraints of the AI backend, such as expected load, latency, and data characteristics. Then propose a high-level architecture, diving into key components like data ingestion, model serving, and scaling. Discuss trade-offs between different design choices, emphasizing Amazon's leadership principles like customer obsession and bias for action.

Pro tip: Quantify your decisions with rough calculations (e.g., QPS, storage needs) to demonstrate practical engineering judgment. Also, relate your design to AWS services (e.g., SageMaker, Lambda, DynamoDB) to show familiarity with Amazon's ecosystem.

1. Clarify Requirements

Ask questions to understand functional and non-functional requirements: what the AI model does, expected traffic, latency, data volume, and consistency needs.

2. High-Level Design

Sketch the main components: data pipeline, model training/serving, API layer, and storage. Explain how they interact.

3. Deep Dive

Elaborate on critical parts: model deployment (real-time vs batch), scaling (horizontal/vertical), and handling failures.

4. Trade-offs & Alternatives

Discuss pros and cons of your choices, such as using serverless vs containers, and how you'd optimize for cost, performance, and scalability.

5. Wrap Up

Summarize the design, mention monitoring and iteration, and tie back to business impact.

Key Points to Mention

  • Scalability and elasticity (auto-scaling, load balancing)
  • Latency and throughput optimization (caching, batching, async processing)
  • Data storage and retrieval (SQL vs NoSQL, data partitioning)
  • Model deployment strategies (A/B testing, canary releases, model versioning)
  • Fault tolerance and availability (redundancy, retries, circuit breakers)
  • Cost efficiency and AWS service selection (e.g., SageMaker, Lambda, S3)

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.