Open by restating the goal in your own words, then pin down constraints: input sizes, data ranges, memory limits, mutation rules, and error conditions. Craft one trivial and one slightly complex example to expose corner cases. Ask targeted questions rather than vague ones, ensuring you lock down expectations early. This disciplined start reduces rework and demonstrates thoughtful engineering instincts that guard quality from the first minute.
Propose a straightforward baseline to ensure correctness, then progress to improved strategies while narrating trade-offs. Quantify time and space complexity at each step, relating choices to constraints. Explain why a data structure or algorithm unlocks performance. Share the decision path, not only the destination. Interviewers learn how you navigate ambiguity, prune options, and keep complexity analysis visible, which mirrors real-world design discussions where clarity trumps cleverness.
Before running, simulate inputs manually, including empty sets, duplicates, extremes, and adversarial cases. Narrate expected results and verify them step by step. If issues appear, propose a minimal refactor with a clear rollback plan, protecting working pieces. This careful, test-first mindset shows discipline under pressure. It also invites collaboration, because you keep your reasoning inspectable, enabling the interviewer to help unblock or refine your approach constructively.