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Walmart·Software Engineer·Technical Phone Screen·Intermediate

IntermediateRejected
Jun 2026

Summary

Got a medium-level DP problem and solved it, but the feedback was that my explanation was hard to follow. Kind of a wake-up call that knowing how to solve something and being able to communicate the solution are very different skills.

Questions Asked (1)

Q1

Solve a medium-difficulty dynamic programming problem and walk through your thought process as you go.

Algorithms & Data Structures
Author's notes

I got the right answer but apparently my verbal explanation was a mess.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the problem and constraints, then define the subproblem and recurrence relation before coding. Implement the DP solution iteratively or recursively with memoization, and analyze time and space complexity while discussing potential optimizations.

Pro tip: Verbalize your thought process clearly, especially when considering trade-offs between different DP approaches, as interviewers value problem-solving skills over just getting the correct answer.

1. Understand the Problem

Restate the problem in your own words, ask clarifying questions about input constraints, expected output, and edge cases.

2. Define Subproblems and State

Identify the subproblems and define the state variables that represent them, explaining what each state means.

3. Formulate Recurrence Relation

Derive the recurrence relation that connects the state to smaller subproblems, and specify base cases.

4. Implement and Optimize

Choose between top-down (memoization) or bottom-up (tabulation) approach, implement the solution, and consider space optimizations if possible.

5. Analyze Complexity and Test

Analyze time and space complexity, then walk through test cases including edge cases to verify correctness.

Key Points to Mention

  • Optimal substructure and overlapping subproblems as DP prerequisites
  • State definition and transition clarity
  • Time and space complexity analysis
  • Trade-offs between memoization and tabulation
  • Edge cases and base cases handling
  • Potential optimizations like rolling arrays or state compression

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