That's a good point! The `15` check relies on 1) knowing it will stop after 15 rounds as written in the problem (though I explore that later) and 2) assuming th

That's a good point! The `15` check relies on 1) knowing it will stop after 15 rounds as written in the problem (though I explore that later) and 2) assuming that there must be a single answer after 15 rounds (which I also explore later). And that's true, the `(i, j)` check is spurious - I blame it on it being throwaway blog post code :)