Weaver is an Android (and probably iOS, too) puzzle game that requires choosing how to twist a mesh of coloured ribbons to match the required output colours.
After a couple of nights of struggling to come up with optimal solutions I decided it's the perfect use case to finally learn Prolog so this is what I came up with. It's been hacked together after only a day of reading manuals and inspired by various Sudoku and Nonograms solvers I found. The method is probably inefficient and the style is definitely horrifying, sorry ;-)
This is known to run on SWI-Prolog (makes some use of nth0 and a couple of other list functions that weren't in GNU prolog).
The required conventions are as follows:
- rotate the puzzle 45 degrees counter-clockwise (so the ribbons come from top and left and go to bottom and right)
- choose a single different lowercase letter for each colour. i tend to go with r for red, y for yellow, g for green, etc. Notation doesn't really matter as long as it's consistent (and lowercase is needed to make Prolog treat colours as constants).
- the input conditions are [InTop,InLeft], where InTop is an array of the incoming vertical ribbons from left to right and InLeft is the aray of the incoming horizontal ribbons from top to bottom)
- the output conditions are [OutBot,OutRight], similar to the input: first the outgoing vertical colours, then the outgoing horizontal colours. In the outputs you can use multi-letter atoms for any ribbon: rgb means it can be either red, green or blue. Don't use quotes.
To run the solver, start swipl in the program directory, run [game]. to load game.pl and query the game predicate in
the with the input and output conditions plus the maximumi number of flips you want (the stars are awarded based on the
number of twists).
For instance, level 1.3 would be game([[r,r],[r,g]],[[r,g],[r,r]],1).. Level 1.6 would be
game([[b,r],[r,y]],[rb,yb],[rb,y]],2).
- replace M with a sparse array to reduce problem space on large boards ( 4.22 is 6x5 and it turns out the problem is finding a sparse enough matrix)
- if M becomes a sparse array, start with 0 flips and increase the length until at least a solution is found
Play store link: https://play.google.com/store/apps/details?id=net.pyrosphere.weaver&hl=en