I'm impressed by your solution.
Ok, because I'm curious I'll show a 'much' longer one with a power
conjunction selector:
T <@((] <@,"1 0 ({::~{:))^:(#@[>{:@]))S:_ 0^:_ <0
Furthermore, counting all paths (paths as meant by R.E. Boss) can be: #
result above verb. But a bit faster are the following sentences (working
bottom up):
indices fold:
0{:: ;(([: < [: +/ ] {::~ ::1:"1 0 {::)`[`]})&.>/ (;/@:i.@#,<)T
39
iterate with 'iterator':
0{:: ;{: (<:@[;<@(([: < [: +/]{::~ ::1:"1 0
{::)`[`]}))&>/^:(#`(<:@#;<))T
39
I'm not a graph expert, so may be there is a clever algorithm (or
combinatorial expression) to obtain the same and as a consequence a nice
J verb.
On 25-04-12 03:38, Thomas Costigliola wrote:
> G=. do;._2]0 :0
> 0 1 2 2 3 4 4 5 5 6 7 7 8 9 10 10 11 11 11 12 12 12
> 1 2 3 4 5 6 5 7 8 7 9 10 10 11 12 11 13 14 15 16 15 14
> )
> ]T=.</./G
> T (<@((]<@,"1 0 {:@]{::[) ::])S:_ 0^:_)<0
>
>
> Challenge: find a verb using the same strategy without using :: and is
> shorter (or not much longer).
>
>
> On Tue, Apr 24, 2012 at 5:01 PM, R.E. Boss<r.e.b...@planet.nl> wrote:
>> No.
>> _.
>>
>>
>> R.E. Boss
>>
>>
>>> -----Oorspronkelijk bericht-----
>>> Van: programming-boun...@jsoftware.com
>>> [mailto:programming-boun...@jsoftware.com] Namens Henry Rich
>>> Verzonden: dinsdag 24 april 2012 22:21
>>> Aan: Programming forum
>>> Onderwerp: Re: [Jprogramming] all paths in a graph
>>>
>>> Can the graph contain a cycle? If so, what should be done?
>>>
>>> Henry Rich
>>>
>>> On 4/24/2012 11:47 AM, R.E. Boss wrote:
>>>> I would like to know other solutions.
>>>> And perhaps learn why it took me so long.
>>>>
>>>>
>>>> R.E. Boss
>>>>
>>>>
>>>>> -----Oorspronkelijk bericht-----
>>>>> Van: programming-boun...@jsoftware.com
>>>>> [mailto:programming-boun...@jsoftware.com] Namens Markus Schmidt-Gröttrup
>>>>> Verzonden: dinsdag 24 april 2012 12:59
>>>>> Aan: Programming forum
>>>>> Onderwerp: Re: [Jprogramming] all paths in a graph
>>>>>
>>>>> I have not investigated in finding an expression for all paths.
>>>>> What for? Efficient graph algorithms as Dijkstra shortest path
>>>>> algorithms avoid the flood of these possibilities.
>>>>>
>>>>> Could you give an idea, what are you aiming at? (Beside staying young)
>>>>>
>>>>> Greetings,
>>>>>
>>>>> Markus
>>>>>
>>>>> Am 24.04.2012 12:39, schrieb R.E. Boss:
>>>>>> Given the directed graph G
>>>>>> (see<http://www.jsoftware.com/jwiki/RE%20Boss>
>>>>>> http://www.jsoftware.com/jwiki/RE%20Boss)
>>> by
>>>>> its edges
>>>>>>
>>>>>>
>>>>>> |: G
>>>>>>
>>>>>> 0 1 2 2 3 4 4 5 5 6 7 7 8 9 10 10 11 11 11 12 12 12
>>>>>>
>>>>>> 1 2 3 4 5 6 5 7 8 7 9 10 10 11 12 11 13 14 15 16 15 14
>>>>>>
>>>>>>
>>>>>>
>>>>>> determine all (different) paths from root 0 to the leaves.
>>>>>>
>>>>>>
>>>>>>
>>>>>> This took me quite some time(days!). Am I getting old?
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> R.E. Boss
>>>>>>
>>>>>>
>>>>>>
>>>>>> ----------------------------------------------------------------------
>>>>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>>>>>
>>>>>>
>>>>> ----------------------------------------------------------------------
>>>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>>> ----------------------------------------------------------------------
>>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>>>
>>> ----------------------------------------------------------------------
>>> For information about J forums see http://www.jsoftware.com/forums.htm
>> ----------------------------------------------------------------------
>> For information about J forums see http://www.jsoftware.com/forums.htm
> ----------------------------------------------------------------------
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--
Met vriendelijke groet,
@@i = Arie Groeneveld
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