[Jprogramming] Advent of code, Day 3 (spoilers probable)

[Raul Miller]

I used Eugene's approach, also:

spiral =: ,~ $ [: /: }.@(2 # >:@i. at -) +/\@# <:@+: $ (, -)@(1&,)
aspiral=: (*: - |."1 at spiral)@>.@%:
steps=:3 :0"0
  as=. aspiral y
  +/|-/(($as)#:I.,1=as),($as)#:I.,y=as
)

   steps 1 12 23 1024
0 3 2 31

FYI,

-- 
Raul

On Mon, Dec 4, 2017 at 2:02 AM, Brian Schott <schott.brian at gmail.com> wrote:
> I have only worked on part 1 so far.
> All my verbs are monadic and take the number in question as its argument.
>
>
>    evenQ =. = <.&.-:
>    size =. (+evenQ)@>.@%:              NB. edge length
>    border =. size-&*:_2+size           NB. border length (number)
>    lowest =. 1 _3 4& p. @ -:@<:@size   NB. border's number which needs
> lowest # of moves
>    least4 =. lowest+ (i. 4)*4%~border  NB. border's 4 lowest # of moves
>    least =. -:@<:@size                 NB. least # of moves
>    addto =: least4<./@:(|@-)]          NB. additional # of moves
>    total =. least + addto
>    total"0]1 12 23 1024
> 0 3 2 31
>
> I found the polynomial in `lowest` by studying the pattern of numbers 1  2
>  11  28 53
> as follows. (The fact that the 2nd differences are constantly 8 lead me to
> the
> solution.)
>
>    2-/\(^: 0 1 2)1 _3 4 p. i. 5
>  1  2  11  28 53
> _1 _9 _17 _25  0
>  8  8   8   0  0
>
>
> I had seen Eugene's evolute and now WRAP, so maybe the second part is
> doable, but I'm tired.
>
> --
> (B=) <-----my sig
> Brian Schott
> ----------------------------------------------------------------------
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