The three bankable cores

Banking behaviors. Every hard FRQ contains a soft core — a behavior you can implement correctly in two minutes. Banking it means: implement it, verify it against the example, and LEAVE it alone. Resist the urge to refactor toward elegance; partial-credit time is spent on points, not beauty.

The three bankable cores, in exam-frequency order:

• The count (or sum) with one condition — almost every FRQ has one.
• The existence check — return true the moment a condition fires; three lines, one early return.
• The single pass with an early sentinel — first-match with a default return at the end.

When the checkpoint asks for the full class, bank coldHours() first, then hasWarmDay(), and only then attempt firstBelow(). If the clock runs out mid-firstBelow, you still banked two of three — the exam version of never losing the whole game.