Clarify Before You Code
The first two minutes of an interview are for questions, not typing. Nailing down inputs, edge cases, and constraints prevents solving the wrong problem.
Key ideas
- —Restate the problem in your own words and confirm it before coding.
- —Ask about input size, ranges, duplicates, empties, and ordering up front.
- —Constraints reveal the intended complexity — they are hints, not trivia.
Why clarification is scored
Interviewers deliberately leave problems underspecified to see whether you surface ambiguity. Restating the task and asking targeted questions — Can the array be empty? Are values unique? Is the input sorted? — signals the requirements-gathering instinct that real engineering demands. Jumping straight to code on an ambiguous prompt is the most common avoidable failure.
Constraints as design hints
The stated limits quietly tell you the expected approach. An input up to a million elements rules out O(n²); a tiny n may invite brute force or bitmask DP; "values fit in 32 bits" hints at bit tricks. Read constraints as the interviewer telling you the target complexity, then design backward from there rather than guessing.
Practice this
Sources
- Cracking the Coding InterviewGayle Laakmann McDowell