Tutorial: solve a DSA problem end-to-end

1. Read carefully. Open a problem and use the mentor's Explain problem quick action to restate it and surface edge cases.
2. Plan before coding. Ask for a level-1 hint if you're unsure of the technique. Aim to name the data structure and approach first.
3. Implement. Write your solution and Run against the samples.
4. Debug. If a case fails, ask the mentor why is this failing? — it sees your code and the failing case.
5. Check complexity. Use Complexity to confirm your time/space is optimal.
6. Submit for the full suite, then add it to Smart Revision so you don't forget it.