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IBM·Software Engineer·Online Assessment (OA)·Intermediate

IntermediatePrefer not to say
Jul 2026

Summary

IBM interview with two problems: a hard DP coding question and a Django backend debugging problem. Didn't finish either cleanly, which stings, but here we are.

Questions Asked (2)

Q1

Solve a hard dynamic programming problem under timed conditions.

Algorithms & Data Structures
Author's notes

Got most of the cases but hit a TLE I couldn't shake.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the problem constraints and edge cases, then define the DP state and recurrence relation before coding. Implement the solution iteratively, test with small examples, and optimize space/time if needed.

Pro tip: Communicate your thought process clearly and prioritize a correct brute-force or memoized solution first, then optimize; interviewers value problem-solving over perfect code under time pressure.

1. Understand the Problem

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

2. Define DP State and Recurrence

Identify the subproblems and define the DP state (e.g., dp[i] represents...). Derive the recurrence relation and base cases.

3. Choose Implementation Strategy

Decide between top-down memoization or bottom-up tabulation based on clarity and efficiency. Consider space optimization if applicable.

4. Code and Test

Write clean code with meaningful variable names. Test with provided examples and edge cases, walking through the logic.

5. Analyze and Optimize

State time and space complexity. Discuss potential optimizations or alternative approaches if time permits.

Key Points to Mention

  • Optimal substructure and overlapping subproblems
  • Time and space complexity analysis
  • Edge cases and base cases
  • Trade-offs between memoization and tabulation
  • Space optimization techniques (e.g., rolling array)
  • Testing and validation with examples

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

Q2

Debug a broken Django backend given a multi-page problem description and supporting documentation.

Root Cause AnalysisAPI & Integrations
Author's notes

Four pages of docs plus the problem statement.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the problem statement and expected behavior, then systematically trace the issue through the Django stack (URLs, views, models, serializers, middleware) using logs, debugger, and tests. Prioritize reproducing the bug in a minimal environment, form hypotheses, and validate fixes with automated tests to prevent regressions.

Pro tip: Demonstrate a methodical, hypothesis-driven approach rather than jumping to code; mention how you'd use Django's debugging tools (e.g., Django Debug Toolbar, logging, pdb) and write a failing test first to confirm the root cause.

1. Understand and Reproduce

Read the problem description and docs carefully to understand expected vs actual behavior. Reproduce the bug locally with a minimal setup, noting exact steps and environment.

2. Gather Evidence

Collect logs, error traces, and database queries. Use Django's logging, debug toolbar, and shell to inspect state at each layer (request, view, model, response).

3. Isolate and Hypothesize

Narrow down the faulty component by selectively disabling middleware, mocking dependencies, or writing unit tests for suspect functions. Form a clear hypothesis about the root cause.

4. Fix and Verify

Implement the minimal fix, then run the failing test to confirm resolution. Check for side effects and ensure no regressions with the full test suite.

5. Communicate and Prevent

Explain the root cause and fix clearly to stakeholders. Suggest improvements like better logging, monitoring, or additional tests to prevent similar issues.

Key Points to Mention

  • Django request/response lifecycle and middleware order
  • Using Django Debug Toolbar, logging, and pdb for debugging
  • Writing a failing test first to confirm the bug and validate the fix
  • Checking database queries and ORM behavior (e.g., N+1, transactions)
  • Reviewing recent code changes or deployments that might have introduced the bug
  • Considering environment differences (settings, dependencies, versions)

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