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Amazon·Software Engineer·Onsite - Multi Round·Junior

JuniorRejected
Jun 2024Santa Clara

Summary

Two back-to-back onsite interviews at Amazon's Santa Clara office for an SDE intern role. Applied in October, OA in March, finally got the in-person in June. Solved most of the technical problems and hit all the behavioral questions, still got rejected with zero feedback after a month of prep and a two-hour commute.

Questions Asked (8)

Q1

Tell me about yourself.

Adaptability & Ambiguity
Author's notes

Did this twice, once per interview.

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AI HintsAI Generated

Suggested Approach

Craft a concise narrative that connects your technical background to Bloomberg's engineering culture, emphasizing adaptability and problem-solving in ambiguous situations. Focus on recent, relevant experiences and how they've prepared you for the challenges of a fast-paced financial technology environment.

Pro tip: Research Bloomberg's engineering principles and recent projects, then subtly align your past experiences with their needs—showing you've done your homework and can hit the ground running.

1. Present

Start with your current role and a high-level summary of your technical expertise, highlighting languages and domains most relevant to Bloomberg.

2. Past

Briefly walk through 1-2 previous roles or projects that demonstrate adaptability, such as navigating unclear requirements or shifting priorities.

3. Proof

Share a specific accomplishment where you solved a complex problem or delivered impact under ambiguity, using metrics if possible.

4. Purpose

Explain why you're interested in Bloomberg and this role, tying your skills to their mission and engineering challenges.

5. Preview

Conclude with what you hope to contribute and learn, showing enthusiasm for the opportunity.

Key Points to Mention

  • Experience with ambiguous or rapidly changing project requirements
  • Proficiency in relevant technologies (e.g., C++, Python, distributed systems)
  • Examples of cross-functional collaboration and communication
  • Interest in financial technology and Bloomberg's data-driven products
  • Ability to learn quickly and adapt to new domains
  • Specific project or achievement that showcases problem-solving under uncertainty

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

Q2

Describe a time you received constructive feedback. How did you respond and what did you take away from it?

Adaptability & Ambiguity
Author's notes

Structured it as situation-action-result and it seemed to land.

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AI HintsAI Generated

Suggested Approach

Choose a specific instance where feedback led to a measurable improvement in your work. Use the STAR method to describe the situation, your response, and the positive outcome, emphasizing your openness to feedback and the concrete steps you took to improve.

Pro tip: Select feedback that highlights a skill relevant to Amazon's Leadership Principles, such as 'Learn and Be Curious' or 'Insist on the Highest Standards.' Show that you not only accepted the feedback but also proactively sought ways to grow from it.

1. Set the Context

Briefly describe the project or situation and the feedback you received, ensuring it's relevant to the role and company.

2. Describe Your Initial Response

Explain how you reacted to the feedback, focusing on your openness and willingness to understand the perspective.

3. Detail Your Action Plan

Outline the specific steps you took to address the feedback, such as additional training, seeking mentorship, or adjusting your approach.

4. Highlight the Outcome

Share the positive results that came from acting on the feedback, using metrics if possible to demonstrate impact.

5. Reflect on the Takeaway

Summarize what you learned and how it has influenced your ongoing professional development.

Key Points to Mention

  • Specific example of constructive feedback received
  • Your immediate and thoughtful response to the feedback
  • Concrete actions taken to implement the feedback
  • Measurable improvement or positive outcome resulting from the feedback
  • Long-term impact on your skills or work ethic
  • Connection to Amazon's Leadership Principles, such as 'Learn and Be Curious' or 'Insist on the Highest Standards'

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

Q3

Tell me about a time you had to deliver something under a tight deadline or significant pressure.

Adaptability & AmbiguityAgile / Sprint Management
Author's notes

Had a decent story ready for this one.

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AI HintsAI Generated

Suggested Approach

Use the STAR method to structure your answer, focusing on a specific instance where you delivered under pressure. Highlight how you prioritized tasks, communicated effectively, and made technical decisions to meet the deadline. Emphasize the outcome and any lessons learned, aligning with Amazon's Leadership Principles like Deliver Results and Bias for Action.

Pro tip: Quantify the impact of your delivery (e.g., 'reduced latency by 30%') and explicitly tie your actions to Amazon's Leadership Principles, such as Ownership and Customer Obsession, to demonstrate cultural fit.

1. Set the Context

Briefly describe the project, the tight deadline or pressure situation, and your role. Keep it concise to focus on your actions.

2. Explain the Challenge

Detail the specific constraints (e.g., time, resources, technical complexity) and why it was challenging. This builds tension and shows the stakes.

3. Describe Your Actions

Walk through the steps you took to overcome the challenge, emphasizing prioritization, collaboration, and technical problem-solving. Use 'I' statements to highlight your contributions.

4. Highlight the Outcome

Share the results: did you meet the deadline? What was the impact on the business or team? Quantify if possible.

5. Reflect and Learn

Briefly mention what you learned or how you improved processes for future high-pressure situations. This shows growth and self-awareness.

Key Points to Mention

  • Prioritization techniques (e.g., MoSCoW, impact/effort matrix) to focus on critical tasks
  • Effective communication with stakeholders to manage expectations and escalate blockers
  • Technical decision-making under pressure (e.g., trade-offs, quick prototyping, leveraging existing solutions)
  • Collaboration and teamwork, such as pair programming or code reviews to maintain quality
  • Metrics or quantifiable results (e.g., delivered X days early, reduced errors by Y%)
  • Alignment with Amazon Leadership Principles (e.g., Deliver Results, Bias for Action, Ownership)

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

Q4

Given a list of strings, group all the anagrams together.

Algorithms & Data Structures
Author's notes

Standard problem, sorted each string as a key and bucketed them.

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AI HintsAI Generated

Suggested Approach

Use a hash map to group strings by a canonical key that is identical for all anagrams. For each string, compute the key (e.g., sorted characters or character count signature) and append the string to the corresponding list. Finally, return all the grouped lists.

Pro tip: Discuss the trade-offs between sorting each string (O(n * k log k)) and using a character count key (O(n * k)), and mention that the count-based approach can be more efficient for long strings with a small alphabet.

1. Clarify and Confirm

Ask clarifying questions about input size, character set, case sensitivity, and whether the output order matters. Confirm that anagrams are case-sensitive and that the list may contain duplicates.

2. Choose a Canonical Key

Decide on a method to generate a unique key for each anagram group. Common approaches: sort the characters of each string, or build a frequency count of characters (e.g., a tuple of 26 counts for lowercase letters).

3. Group with a Hash Map

Iterate through the list, compute the key for each string, and use a hash map to map the key to a list of strings. Append the current string to the list for its key.

4. Return the Groups

After processing all strings, return the values of the hash map as a list of lists. If the problem requires a specific order, sort the groups or the strings within groups accordingly.

5. Analyze Complexity

State the time and space complexity. For sorting approach: O(n * k log k) time, O(n * k) space. For counting approach: O(n * k) time, O(n * k) space, where n is the number of strings and k is the maximum length.

Key Points to Mention

  • Hash map usage for grouping
  • Canonical key generation (sorting vs. character count)
  • Time and space complexity analysis
  • Handling edge cases (empty strings, single string, all anagrams, no anagrams)
  • Trade-offs between different key generation methods
  • Potential for using prime number multiplication as a key (though overflow concerns)

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

Q5

Find all contiguous subarrays whose elements sum to a target value k.

Algorithms & Data Structures
Author's notes

Prefix sum with a hashmap.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the problem constraints (e.g., positive/negative numbers, return indices or values, handle duplicates). Then present the optimal prefix sum + hash map solution, explaining how it achieves O(n) time by storing cumulative sums and checking for target - current_sum. Walk through a small example to demonstrate correctness and edge cases.

Pro tip: Mention that for positive numbers only, a sliding window approach works, but the prefix sum method is more general and handles negatives. Also, discuss how to handle duplicate subarrays and whether to return all or just count them.

1. Clarify requirements and constraints

Ask about input size, whether numbers can be negative, if subarrays must be non-empty, and what to return (indices, values, or count). This shows attention to detail and avoids incorrect assumptions.

2. Discuss brute force and its limitations

Mention the O(n^2) approach of checking all subarrays, but note it's inefficient for large inputs. This sets the stage for optimization.

3. Introduce prefix sum with hash map

Explain that a running sum (prefix sum) combined with a hash map storing sum frequencies allows O(n) time. For each element, check if (current_sum - k) exists in the map, and add the current sum to the map.

4. Walk through an example and handle edge cases

Use a small array to demonstrate the algorithm step-by-step. Discuss edge cases like empty array, k=0, and negative numbers. Mention that the map initially contains {0:1} to handle subarrays starting at index 0.

5. Analyze complexity and potential optimizations

State time complexity O(n) and space O(n). If only positive numbers, mention sliding window O(n) time O(1) space. Also, discuss how to modify to return actual subarrays instead of just count.

Key Points to Mention

  • Prefix sum concept: cumulative sum up to each index.
  • Hash map to store prefix sum frequencies for O(1) lookups.
  • Handling negative numbers and zero target.
  • Initializing map with {0:1} to account for subarrays starting at index 0.
  • Time and space complexity: O(n) time, O(n) space.
  • Alternative sliding window for positive numbers only.

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

Q6

Walk me through a technical project you worked on. What did you struggle with, what problems did you solve, and what would you do differently?

Technical Trade-offsSystem Design
Author's notes

The manager asked around seven follow-ups off this single question.

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AI HintsAI Generated

Suggested Approach

Choose a project that showcases technical depth and aligns with Amazon's Leadership Principles, such as Ownership and Customer Obsession. Structure your answer using the STAR method, focusing on the problem, your specific actions, and the measurable impact. Highlight the trade-offs you considered and what you learned from the experience.

Pro tip: Emphasize the 'why' behind your decisions and how you incorporated feedback or data to improve. Show that you're not just a coder but a problem-solver who thinks about business impact and customer value.

1. Set the Context

Briefly describe the project, your role, and the business goal. Keep it concise to save time for the technical details.

2. Explain the Technical Challenge

Detail the specific technical problem you faced, including constraints and requirements. Mention any trade-offs you had to consider.

3. Describe Your Actions

Walk through the steps you took to solve the problem, highlighting your individual contributions and the technologies used.

4. Share the Outcome

Quantify the results: performance improvements, cost savings, user impact, etc. If possible, relate it to customer experience.

5. Reflect on Lessons Learned

Discuss what you would do differently and how you've applied those lessons to subsequent projects. Show growth and self-awareness.

Key Points to Mention

  • Specific technologies and architecture used (e.g., microservices, AWS services)
  • Trade-offs considered (e.g., consistency vs. availability, cost vs. performance)
  • Metrics that demonstrate impact (e.g., latency reduction, cost savings)
  • Collaboration with cross-functional teams (e.g., product managers, QA)
  • How you handled ambiguity or changing requirements
  • Alignment with Amazon Leadership Principles (e.g., Ownership, Dive Deep)

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

Q7

How do you use generative AI tools in your projects? Walk me through a specific example.

Adaptability & AmbiguityTechnical Trade-offs
Author's notes

Wasn't expecting this to be a formal interview question.

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AI HintsAI Generated

Suggested Approach

Choose a specific project where you used generative AI to solve a real problem, and structure your answer using the STAR method. Highlight the trade-offs you considered, how you handled ambiguity, and the measurable impact of your solution. Emphasize Amazon's leadership principles like Customer Obsession, Invent and Simplify, and Deliver Results.

Pro tip: Show that you treat generative AI as a tool, not a silver bullet—discuss how you validated its output and integrated it responsibly. Mention any guardrails or fallback mechanisms you implemented to mitigate risks like hallucinations or bias.

1. Set the Context

Briefly describe the project, your role, and the problem you were solving. Explain why generative AI was a suitable approach and what alternatives you considered.

2. Detail the Implementation

Walk through how you integrated the generative AI tool: which model or API you used, how you prompted it, and how you handled data privacy and security. Mention any technical challenges and how you overcame them.

3. Discuss Trade-offs and Decisions

Explain the key trade-offs you made, such as accuracy vs. cost, latency vs. quality, or build vs. buy. Show how you evaluated options and made a decision aligned with business goals.

4. Highlight Validation and Guardrails

Describe how you tested and validated the AI's output, including any automated checks, human review, or fallback mechanisms. Emphasize responsible AI practices.

5. Share Results and Learnings

Quantify the impact: time saved, cost reduced, accuracy improved, or customer satisfaction increased. Reflect on what you learned and how you would improve next time.

Key Points to Mention

  • Specific generative AI tool used (e.g., OpenAI GPT, Amazon Bedrock, GitHub Copilot) and why you chose it.
  • How you ensured data privacy and security, especially if using external APIs.
  • Trade-offs considered: cost, latency, accuracy, scalability, and maintainability.
  • Validation techniques: unit tests, prompt engineering, human-in-the-loop, or automated evaluation.
  • Measurable impact: e.g., reduced development time by X%, improved code quality, or enhanced customer experience.
  • Alignment with Amazon Leadership Principles: Customer Obsession, Invent and Simplify, Deliver Results, Learn and Be Curious.

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

Q8

Design an algorithm to determine how many cars passed through a given intersection during a specific time window, using GPS coordinates and timestamps.

Algorithms & Data StructuresSystem Design
Author's notes

This one genuinely surprised me, I was expecting a standard leetcode-style coding question and got an algorithm design problem instead.

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AI HintsAI Generated

Suggested Approach

Clarify the problem scope first: define the intersection area, time window, and data format. Then propose a scalable algorithm that filters GPS points by time and spatial proximity, and counts unique vehicles using a vehicle identifier. Discuss trade-offs between accuracy and efficiency, and consider distributed processing for large datasets.

Pro tip: Mention that GPS data is noisy and may have gaps, so you'd use a geofence with a buffer and deduplicate by vehicle ID to avoid double-counting. Also, discuss how to handle late-arriving data and out-of-order timestamps.

1. Clarify Requirements

Ask about the intersection definition (radius or polygon), time window granularity, data volume, and whether vehicle IDs are available. Confirm if real-time or batch processing is needed.

2. Design Data Model

Assume GPS points have vehicle_id, timestamp, latitude, longitude. Define the intersection as a geofence (e.g., circle with radius R). Consider indexing by time and space.

3. Algorithm Design

Filter points within the time window and geofence. Group by vehicle_id and count distinct vehicles. For scalability, use a distributed framework like MapReduce or Spark, partitioning by time and space.

4. Handle Edge Cases

Address GPS noise (use buffer), missing data (interpolation), duplicate points, and vehicles that pass through without a point exactly inside (use trajectory intersection).

5. Optimize and Scale

Discuss indexing (e.g., geohash, R-tree), streaming vs batch, and approximate counting (HyperLogLog) for large-scale. Mention trade-offs between accuracy and performance.

Key Points to Mention

  • Geofencing and spatial indexing (e.g., geohash, R-tree) to efficiently filter points near the intersection.
  • Deduplication by vehicle ID to count unique cars, not GPS points.
  • Handling GPS noise and inaccuracies with a buffer zone or probabilistic methods.
  • Scalability using distributed processing (MapReduce, Spark) and partitioning by time and space.
  • Streaming vs batch processing: Lambda architecture for real-time and historical analysis.
  • Approximate counting algorithms (HyperLogLog) for high-volume data when exact counts are not required.

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