The working method

This course assumes the full AP CSA toolkit. Nothing is labeled anymore. Problems arrive the way the exam delivers them — a specification plus some code — and your job is to decide what matters before writing a single line. That is a skill, and skills are trained by reps.

The method used all course long:

1. Restate the spec in one sentence: inputs → outputs, what changes.
2. Type the data: what is int, what is String, what is a reference? References alias — two variables can name one object.
3. Find the boundaries: empty, size 1, first/last index, zero, cap.
4. Pick the smallest correct algorithm and only optimize if the spec demands it.
5. Trace your own code once before submitting — always.

Overthinking is the classic advanced failure: a spec that says one pass, no removals does not want nested loops. Under-thinking is worse: a spec that says each item may affect the next demands a state you must carry between iterations.