I'd meet that specification like this:
require'stats'
perms=: A.&i.~ !
gen=:4 :0
x{~,/(perms y){"1/y comb #x
)
But note that the result format is different.
Thanks,
--
Raul
On Tue, Aug 15, 2017 at 12:58 PM, Skip Cave <[email protected]> wrote:
> I believe that the general case would be:
> Design a J verb that will generate all possible unique strings of a
> specific fixed length using only specified set of symbols, where each
> generated string has no repeated symbols.
>
> x gen y
>
> Where x specifies a set of symbols (characters, numbers), and y specifies
> the symbol string length (this length must be the same or less than the
> number of symbols)
>
> '12ab' gen 3
> 12a 12b 1a2 1b2 1ab 1ba 21a 21b 2a1 2b1 a12 a21 a1b a2b b12 b21 .....
>
> Then one could really test algorithm efficiency using large symbol sets and
> large string lengths.
>
> Skip
>
>
> Skip Cave
> Cave Consulting LLC
>
> On Tue, Aug 15, 2017 at 11:32 AM, Don Guinn <[email protected]> wrote:
>
>> For really big problems you could go to a larger base than 10 like
>> hexadecimal. Or even bigger using more letters.
>>
>> On Tue, Aug 15, 2017 at 10:10 AM, Raul Miller <[email protected]>
>> wrote:
>>
>> > To compare them for equality you need to sort them.
>> >
>> > However, the task was to generate the integers.
>> >
>> > (If the example list of numbers was a part of the specification then
>> > we probably should not be considering seven digit integers as
>> > relevant.)
>> >
>> > Thanks,
>> >
>> > --
>> > Raul
>> >
>> > On Tue, Aug 15, 2017 at 10:37 AM, Arie Groeneveld
>> > <[email protected]> wrote:
>> > > To compare both you need to do the following:
>> > >
>> > > 10 ts 'R=./:~,10#.(perms 7){"1/1+7 comb 9'
>> > > 0.0288779 2.4132e7
>> > > 10 ts 'G=.,10 #. ((],"1 0 -."1)^:6 ,.)1+i.9'
>> > > 0.0258377 2.30737e7
>> > > R-:G
>> > > 1
>> > >
>> > > Looks like a draw.
>> > >
>> > >
>> > > Op 15-08-17 om 16:16 schreef Raul Miller:
>> > >>
>> > >> I cannot comment on elegance, but I can disagree about the efficiency
>> > >> issue:
>> > >>
>> > >> timespacex ',10#.(perms 7){"1/1+7 comb 9'
>> > >> 0.015591 2.15104e7
>> > >> timespacex '10 #. (,/@:(],"1 0 -."1)^:6 ,.)1+i.9'
>> > >> 0.036695 3.7755e7
>> > >>
>> > >> Thanks,
>> > >>
>> > >
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