hey! this is a really good port of the game, thank you! I downloaded this over on tic80.com and fixed the autoplay algorithm because I thought it would be an interesting puzzle. my fixed version is up at https://pastebin.com/5Pe41Pzn – if you don’t have the Pro version you can just copy and paste the code into the editor over what’s present in the .tic file.
the patched version moves any reachable value card (of rank x) to its foundation when:
- its own foundation contains the card at rank
x-1 - the other two foundations contain at least their corresponding cards at rank
x-2, if that card exists
this moves every card that never needs to be built upon. each value card can be the target for two other cards (rank x-1, different suit), except for value 1. so if both rank x-1 cards of other suits are on the foundations, the card is trivially safe to move because no cards remain available that could be put on it. (and the x-1 rank card of the same suit has to be in the foundation so card x can be put there!)
but that logic can be iterated! the two cards that could be put on top of a card that could be moved to a foundation can themselves be safely moved to a foundation if their x-1 cards are all on the foundations. so relative to our original rank, we can accept x-2 as the minimum rank of the foundations, except our own.
we can’t iterate this further, since then our reasoning would rely on being able to move cards straight to the foundation when the cards they’d need to stack on top of aren’t actually on the foundation yet, although auto-move might discover it’s valid after other auto-moves make the foundations catch up.
I’m pretty sure this is the same algorithm used in SHENZHEN I/O itself.