Got this:
cl=: [: {:"1 ] ([: ; lp&.>/"1)@]^:(*./@:~: {:@>@{:"1)^:_ lp
lp=: [ ((-. (,: |.)@(_2&{.)) ; ])"2 1 ] ,"1 0 {:"1@[ {~ {:@] I.@:=
{."1@[
Not particularly elegant or concise, but it works (G -: edges):
((, |."1) G) cl 1
1 2 4 5 6 7 8 9 10 11 12 13 24 25 26 23 16 15 14 22 21 20 19 18
17 3 1
1 3 17 18 19 20 21 22 14 15 16 23 26 25 24 13 12 11 10 9 8 7 6 5
4 2 1
It will find all shortest cycles in the graph x, starting at y. The
modification of G is to make it undirected; cl works on
directed graphs as well (I think!).
I believe this modification will make it less efficient, but it will find _all_
cycles in the graph:
cls=: [: {:"1 ] ([: ; <@(lp&>/@]`(,:@])@.(= {:@>@{:))"1)^:_ lp
However I haven’t tested it on another graph yet, so don’t take my word for it.
Nice challenge, thank you.
Cheers,
Louis
> On 25 Aug 2016, at 12:13, R.E. Boss <[email protected]> wrote:
>
> 1 2 4 5 6 7 8 9 10 11 12 13 24 25 26 23 16 15 14 22 21 20 19 18 17 3 1
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