← DoorDash Interview Insights

DoorDash·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
May 2026

Summary

DoorDash ran a pretty unusual coding round where you're not allowed to write any code yourself. You have to prompt AI tools like Cursor or Copilot, paste in what they generate, and iterate until the tests pass. The interviewer is watching how you think and decompose the problem, not whether you can type fast.

Questions Asked (1)

Q1

Given a problem statement and a partial codebase, solve it entirely through AI coding tools by writing prompts and iterating on the generated code until all tests pass. No writing code yourself.

Technical Trade-offsAdaptability & AmbiguityAlgorithms & Data Structures
Author's notes

This format genuinely threw me.

Create a free account to read the full note

AI HintsAI Generated

Suggested Approach

Demonstrate a structured workflow for using AI coding tools: first restate the problem and constraints, then break it into small, testable units. Write precise prompts for each unit, run tests, and iteratively refine prompts based on failures. Emphasize that you never write code manually but guide the AI with clear specifications and debugging feedback.

Pro tip: Treat the AI as a junior engineer: give it context, constraints, and examples, and always verify its output with tests. When tests fail, don't just say 'fix it'—provide the exact error and expected behavior to get a targeted fix.

1. Understand and Decompose the Problem

Read the problem statement and partial codebase carefully. Identify inputs, outputs, edge cases, and constraints. Break the solution into small, independent functions or modules that can be tested separately.

2. Craft Precise Prompts for Each Unit

For each unit, write a prompt that includes the function signature, expected behavior, input/output examples, and any relevant code context. Ask the AI to generate code and tests for that unit.

3. Run Tests and Analyze Failures

Execute the generated tests. If they fail, capture the exact error messages and identify which unit is problematic. Determine whether the issue is in the prompt, the generated code, or the test itself.

4. Iterate with Targeted Prompts

Refine the prompt by adding the failure details, clarifying edge cases, or providing counterexamples. Ask the AI to fix the specific issue without breaking other parts. Repeat until all tests pass.

5. Integrate and Validate End-to-End

Once individual units pass, integrate them and run the full test suite. If integration fails, use prompts to adjust interfaces or data flow. Ensure the final solution meets all requirements.

Key Points to Mention

  • Prompt engineering: being specific about inputs, outputs, constraints, and examples.
  • Iterative development: using test failures as feedback to refine prompts.
  • Decomposition: breaking the problem into small, testable units to isolate issues.
  • Verification: relying on automated tests to validate AI-generated code.
  • Adaptability: adjusting strategy when AI produces incorrect or inefficient code.
  • Trade-offs: balancing speed of AI generation with correctness and maintainability.

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