Your input isn't the problem.
$: can be a big source of innefficiency, as it has to keep all past results in
memory.
timespacex 'v^:(20) 3 1 1 3 3 2 2 1 1 3'
0.0475805 6.57267e6
timespacex ',@((# , {.);.1~ (~: |.!.0))^:20 ] 3 1 1 3 3 2 2 1 1 3'
0.00126528 152192
crashes for me at v^:24.
the string gets very long, and you are calling $:@tail 100k times+ on the list
at around 20 iterations. The combination with $: is deadly.
________________________________
From: Brian Schott <schott.br...@gmail.com>
To: Programming forum <programm...@jsoftware.com>
Sent: Saturday, December 12, 2015 8:57 PM
Subject: Re: [Jprogramming] advent 10
My attempt fails with a stack error after about power of 25, so I cannot
use it to solve day 10, really.
The code below can be used as follows, but 40 cannot replace 25. I tried M.
but with no effect. Any other recommendations would be appreciated.
NB. v ^: (25) 3 1 1 3 3 2 2 1 1 3
Notice that I elected to use 3 1 1 3 3 2 2 1 1 3 to start and I noticed
others some chose to use instead of 1 1 1 3 2 2 2 1 1 3 (I think Henry has
a typo in his version, btw). I don't understand why that choice was made.
m66 =: 1 ,~ 2 ~:/\ ]
headNo =: (1 + (i.&1))@m66
head =: headNo{.]
tail =: headNo}.]
next =: headNo , ({.@head)
v =: ]`(1,])`($:@:tail,~next)@.(2<.#)
On Thu, Dec 10, 2015 at 4:29 PM, Henry Rich <henryhr...@gmail.com> wrote:
> We all had the same solution. My version is
>
> # ,@((# , {.);.1~ (~: |.!.0))^:40 "."0 '1113122113'
>
> Henry Rich
>
>
>
--
(B=)
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