The sample solution clearly does not meet many students' expectation of what they expect to see. Yes, it will be changed and explained/clarified, particularly with regard to how and when state transitions are implemented. The goal is to define, and require, a very simple implementation, not one with clever optimisations, so that all students can aim for the same (numeric) results. But it's been a very busy last couple of days for me (with lots of non-2002 things), and I hope to get back to it today.