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Akuna Capital·Software Engineer·Onsite - Multi Round·Intermediate

IntermediateRejected
Jul 2026

Summary

Went through the full Akuna Capital C++ SWE process: an OA, a debugging assessment, and four technical rounds. Made it all the way through but got cut before the final round, mostly because the in-interview debugging was brutal for someone who primarily writes Java.

Questions Asked (5)

Q1

Implement or simulate a real-world scenario in C++ (non-LeetCode style coding problem from the OA).

Algorithms & Data StructuresTechnical Trade-offs
Author's notes

The OA problems were not the grind-LeetCode-mediums type.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the scenario and requirements with the interviewer, then outline a modular design using appropriate data structures and algorithms. Implement a clean, testable solution in C++ while explaining your design choices and trade-offs as you code.

Pro tip: Focus on code quality and communication: write readable code with meaningful names, handle edge cases, and discuss potential improvements even if you don't have time to implement them.

1. Clarify Requirements

Ask questions to understand the problem scope, constraints, and expected behavior. Confirm input/output formats and any performance requirements.

2. Design the Solution

Outline a high-level design, choosing appropriate data structures and algorithms. Discuss trade-offs (e.g., time vs. space, simplicity vs. extensibility).

3. Implement Incrementally

Code the solution in logical chunks, testing each part as you go. Use clear naming and modular functions to keep the code organized.

4. Test and Validate

Walk through test cases, including edge cases and potential failures. Verify correctness and discuss how you would handle errors.

5. Review and Optimize

If time permits, review the code for improvements, such as performance optimizations or code clarity. Summarize the solution and its trade-offs.

Key Points to Mention

  • Choice of data structures and algorithms with justification
  • Time and space complexity analysis
  • Modular design and separation of concerns
  • Error handling and edge cases
  • Testing strategy and validation
  • Potential optimizations and trade-offs

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

Q2

Identify and fix multiple bugs in a provided C++ codebase within a 45-minute window.

Root Cause AnalysisTechnical Trade-offs
Author's notes

The standalone debugging assessment felt manageable.

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AI HintsAI Generated

Suggested Approach

Start by quickly reading the problem statement and scanning the code to understand its purpose and identify obvious issues. Then systematically debug by reproducing errors, using a debugger or print statements, and fixing one bug at a time while verifying each fix. Prioritize bugs that block compilation or cause crashes, then address logical errors, and finally optimize if time permits.

Pro tip: Communicate your thought process continuously—interviewers value how you approach problems and handle trade-offs more than just fixing all bugs. If stuck, explain your hypothesis and how you'd test it, showing structured debugging.

1. Understand the Code and Requirements

Read the problem statement and skim the code to grasp its intended functionality and constraints. Identify the programming language, libraries, and any provided tests or examples.

2. Reproduce and Prioritize Bugs

Compile and run the code to see failures. List all observed issues, then prioritize by severity: compilation errors, crashes, incorrect outputs, and performance problems.

3. Debug Systematically

Use a debugger, print statements, or unit tests to isolate each bug. Form hypotheses, test them, and fix one bug at a time, ensuring each fix doesn't introduce new issues.

4. Verify and Refactor

After fixing, re-run tests and check edge cases. Refactor if needed for clarity or efficiency, but avoid over-engineering under time pressure.

5. Communicate and Summarize

Explain your fixes, the root causes, and any trade-offs made (e.g., quick fix vs. robust solution). Summarize what you learned and how you'd prevent similar bugs.

Key Points to Mention

  • Root cause analysis: identify why the bug occurs, not just the symptom.
  • Prioritization: fix critical bugs first (e.g., crashes) before minor issues.
  • Testing: use unit tests or manual test cases to verify fixes and prevent regressions.
  • Trade-offs: balance between quick fixes and long-term maintainability under time constraints.
  • Communication: verbalize your debugging process and reasoning to the interviewer.
  • Edge cases: consider boundary conditions and input validation that might be overlooked.

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

Q3

Discuss C++ memory management: how it works, common pitfalls, and how you handle it in practice.

Technical Trade-offsSystem Design
Author's notes

Expected this one.

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AI HintsAI Generated

Suggested Approach

Start by explaining the fundamental mechanisms of C++ memory management (stack, heap, RAII, smart pointers), then discuss common pitfalls like leaks and dangling pointers, and finally describe your practical strategies for writing safe and efficient code, emphasizing modern C++ best practices and tools.

Pro tip: Demonstrate awareness of trade-offs: for low-latency systems like trading, manual memory management with custom allocators can outperform smart pointers, but you must weigh safety and maintainability. Mention profiling and static analysis tools to show a proactive approach.

1. Explain the Basics

Briefly describe stack vs heap allocation, the role of new/delete, and how RAII and smart pointers (unique_ptr, shared_ptr) automate memory management.

2. Identify Common Pitfalls

Discuss frequent issues: memory leaks, dangling pointers, double frees, buffer overflows, and ownership ambiguity, with examples.

3. Describe Practical Strategies

Outline your approach: prefer smart pointers and RAII, use containers instead of raw arrays, follow the Rule of 0/3/5, and employ tools like Valgrind, AddressSanitizer, and static analyzers.

4. Discuss Performance Considerations

Explain when manual memory management or custom allocators might be necessary for performance, and how you balance safety with efficiency.

5. Conclude with Best Practices

Summarize key takeaways: write clear ownership semantics, use modern C++ features, and test thoroughly with sanitizers and code reviews.

Key Points to Mention

  • RAII and smart pointers (unique_ptr, shared_ptr, weak_ptr) for automatic resource management
  • Common pitfalls: memory leaks, dangling pointers, double deletion, and buffer overflows
  • Rule of 0/3/5 for resource-managing classes
  • Tools: Valgrind, AddressSanitizer, static analyzers (e.g., Clang-Tidy)
  • Performance trade-offs: custom allocators, memory pools for low-latency systems
  • Modern C++ features: move semantics, perfect forwarding, and standard containers

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

Q4

Explain multithreading and concurrency concepts in C++ and how you'd approach thread safety in a real system.

System DesignTechnical Trade-offs
Author's notes

They went deeper than I expected here.

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AI HintsAI Generated

Suggested Approach

Start by defining multithreading and concurrency in C++ and distinguishing them, then discuss common challenges like data races and deadlocks. Transition to a structured approach for ensuring thread safety in a real system, emphasizing trade-offs and practical techniques.

Pro tip: Demonstrate maturity by acknowledging that thread safety often involves trade-offs between performance and correctness, and that over-synchronization can be as harmful as under-synchronization. Mention that you'd start with the simplest correct solution and optimize only when profiling shows contention.

1. Define Core Concepts

Clearly explain multithreading (multiple threads within a process) and concurrency (tasks making progress in overlapping time periods), and how C++ supports them via std::thread, std::async, etc.

2. Identify Challenges

Discuss common pitfalls: data races, deadlocks, livelocks, race conditions, and memory model issues (e.g., atomicity, visibility, ordering).

3. Outline Thread Safety Strategies

Describe techniques: mutexes, locks (std::lock_guard, std::unique_lock), atomics, condition variables, thread-local storage, lock-free programming, and higher-level abstractions like thread pools.

4. Apply to a Real System

Walk through a concrete example (e.g., a trading system) where you'd identify shared data, choose synchronization primitives, minimize critical sections, and consider scalability and performance.

5. Discuss Trade-offs and Testing

Highlight trade-offs (e.g., lock contention vs. complexity), and mention testing strategies like stress tests, race detectors (ThreadSanitizer), and code reviews.

Key Points to Mention

  • Difference between multithreading and concurrency, and C++ memory model (std::memory_order).
  • Common synchronization primitives: mutexes, condition variables, atomics, and their appropriate use cases.
  • RAII for lock management (std::lock_guard, std::unique_lock) to avoid deadlocks and ensure exception safety.
  • Techniques to minimize contention: reducing critical section size, using read-write locks, and lock-free data structures.
  • Importance of testing and tools: ThreadSanitizer, stress testing, and static analysis.
  • Real-world example: designing a thread-safe queue or order book for a trading system.

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

Q5

Walk through low-level performance optimizations in C++: what you'd look for and how you'd approach them.

Technical Trade-offsSystem Design
Author's notes

This one I mostly fumbled.

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AI HintsAI Generated

Suggested Approach

Start by emphasizing a measurement-driven approach: profile first to identify bottlenecks, then apply targeted optimizations. Structure your answer around a systematic methodology covering memory, CPU, and compiler-level optimizations, and illustrate with concrete examples from your experience. Conclude by discussing trade-offs and the importance of maintaining code readability and correctness.

Pro tip: Mention that premature optimization is the root of all evil, but also highlight that in latency-sensitive domains like trading, every microsecond counts—so you need to know when to optimize and when to stop. Show that you understand the business context and can balance performance with maintainability.

1. Profile and Identify Bottlenecks

Use profiling tools (e.g., perf, VTune, gprof) to find hotspots and measure baseline performance. Focus on the critical path and avoid optimizing code that isn't hot.

2. Optimize Memory Access and Data Layout

Improve cache locality by using contiguous data structures (e.g., arrays of structs vs. structs of arrays), minimizing pointer chasing, and aligning data to cache lines. Consider custom allocators or memory pools to reduce allocation overhead.

3. Reduce CPU Work and Improve Instruction-Level Parallelism

Eliminate redundant computations, use branch prediction hints, and leverage SIMD instructions where applicable. Consider algorithmic improvements (e.g., O(n log n) to O(n)) and avoid unnecessary virtual calls or exceptions in hot paths.

4. Leverage Compiler and Language Features

Enable compiler optimizations (-O2/-O3, -march=native), use inline functions, constexpr, and move semantics. Understand the impact of RVO, NRVO, and avoid unnecessary copies.

5. Validate and Iterate

Measure the impact of each optimization, ensure correctness with tests, and document trade-offs. Be prepared to revert changes that don't yield significant gains or harm readability.

Key Points to Mention

  • Profiling tools and techniques (e.g., perf, VTune, flame graphs) to identify hotspots
  • Cache-friendly data structures and memory layout optimizations (e.g., SoA vs. AoS, alignment)
  • Compiler optimizations and flags (e.g., -O3, -march=native, LTO, PGO)
  • Avoiding unnecessary allocations and using custom allocators or memory pools
  • Branch prediction, loop unrolling, and SIMD vectorization
  • Trade-offs between performance, readability, and maintainability

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