Coding Interview: Patterns & DSA · Interview Execution · Lesson 1 of 1
Clarify → plan → code → verify
Interviewers grade your process as much as your solution — narrating your reasoning, trade-offs, and testing is explicitly scored, not a nicety. Strong candidates run the same loop every time, so the structure survives nerves.
- Clarify: restate the problem in your own words. Ask about input ranges, duplicates, empties, negatives, and expected scale — the constraints tell you the target complexity.
- Plan out loud: name the brute force and its complexity first, then the pattern that beats it. Get a nod on the approach before writing code.
- Code while narrating: say what each block does as you write it. Silence reads as being stuck even when you aren't.
- Verify: trace one small example line by line, then the edge cases you clarified. Finish by stating final time and space.
Constraints are the hint
n up to 10^5 means O(n^2) will not pass — think O(n log n) or O(n). n <= 20 invites O(2^n) backtracking. Reading the bounds aloud and naming the implied budget is a senior move that takes ten seconds.AI-assisted rounds
Some companies now put an AI assistant in the interview editor and grade how you prompt, validate, and debug its output; others explicitly ban tools. Prepare the same way for both: state your approach before generating anything, then treat generated code like a pull request to review — check its complexity against the constraints, trace the edge cases, and narrate what you are verifying. The pattern knowledge in this track is what lets you catch an O(n^2) suggestion when the bounds demand O(n log n).
Coding before agreeingDiving into code before the interviewer buys the approach is the most common self-inflicted failure: you burn ten minutes on a solution they would have redirected in one. The plan step costs two minutes and buys you a collaborator.
Debug visiblyWhen a test fails, trace the failing input through your own code, narrating each variable — do not rewrite from scratch or resubmit hopefully. Watching you localize a bug methodically is worth more than a first-try pass.
◆ Lock it in
- Run the loop: clarify → plan → code → verify — the process is scored, not just the output.
- Read the constraints aloud; they set the complexity budget before you pick a pattern.
- In AI-assisted rounds, treat generated code as a review target: check complexity, trace edges, narrate.
Feynman drill — say it out loudExplain how you would spend the first five minutes of a 35-minute coding interview, and why writing code immediately is a mistake.
Step 1 rate your confidence · Step 2 pick your answer
Your solution fails one test case with ten minutes left. The strongest move is:
Step 1 — how sure are you?