Ok...
I didn't feel like trying to make this tacit:
updowns=:{{
undx=. +/\ 2 ~:/\ (,~ 1+{.) y
uval=. undx {./. y
ucnt=. #/.~ undx
useg=. ((2 ~:/\ ]),0#~0<#) * 2 -/\ uval
reps=. ucnt*1,1+useg
sndx=. +/\reps
segs=. (1,useg) (sndx-ucnt)} 0#~{:sndx
segs<;.1 reps#uval
}}
This is of course quite a bit longer than your Foo, but also somewhat
faster on long sequences in my trivial tests.
It's less space efficient, perhaps because I've retained all
intermediate results until the end.
I hope this helps,
--
Raul
On Fri, May 21, 2021 at 7:21 AM R.E. Boss <r.e.b...@outlook.com> wrote:
>
> Yep.
>
>
> R.E. Boss
>
>
> -----Original Message-----
> From: Programming <programming-boun...@forums.jsoftware.com> On Behalf Of
> Raul Miller
> Sent: vrijdag 21 mei 2021 12:47
> To: Programming forum <programm...@jsoftware.com>
> Subject: Re: [Jprogramming] ups & downs
>
> Ok... so... this is correct behavior?
>
> Foo 1 10 1 # 1 2 1
> +---------------------+---------------------+
> |1 2 2 2 2 2 2 2 2 2 2|2 2 2 2 2 2 2 2 2 2 1|
> +---------------------+---------------------+
>
> Thanks,
>
> --
> Raul
>
>
> On Fri, May 21, 2021 at 4:09 AM R.E. Boss <r.e.b...@outlook.com> wrote:
> >
> > ud 2#1 2 1 2 1
> > +-------+-----+-----+-----+
> > |1 1 2 2|2 1 1|1 2 2|2 1 1|
> > +-------+-----+-----+-----+
> > Foo 2#1 2 1 2 1
> > +-------+-------+-------+-------+
> > |1 1 2 2|2 2 1 1|1 1 2 2|2 2 1 1|
> > +-------+-------+-------+-------+
> >
> > the latter being the required, maximal length ups & downs.
> >
> > OTOH, Foo does not handle correct your first two values 4#1 and 3#1 2.
> > But they are rather trivial ones, being constant or only one up (or down),
> > I can live with that. An easy check could filter that out.
> >
> >
> > R.E. Boss
> >
> >
> > -----Original Message-----
> > From: Programming <programming-boun...@forums.jsoftware.com> On Behalf Of
> > Raul Miller
> > Sent: vrijdag 21 mei 2021 00:32
> > To: Programming forum <programm...@jsoftware.com>
> > Subject: Re: [Jprogramming] ups & downs
> >
> > Bugfix:
> >
> > reps=: 1+0,~0,2~:/\[:[^:(0~:[)/\.&|.^:2@:*2 -/\]
> > ud=: reps ((1,2 =/\ [ # #\@]) <;.1 #) ]
> >
> > This fixes a problem where the duplicate values appeared at the end of the
> > sequence.
> >
> > Here are some values to test against:
> > 4#1
> > 3#1 2
> > 2#1 2 1 2 1
> >
> > I think I've dealt with all of these correctly (though of course, there's
> > some ambiguity where a run of equal values appears at the edge of an
> > up/down border). But let me know if I should be doing this differently.
> >
> > Thanks,
> >
> > --
> > Raul
> >
> > On Thu, May 20, 2021 at 12:17 PM Raul Miller <rauldmil...@gmail.com> wrote:
> > >
> > > Oh... I see...
> > >
> > > I noticed that the ravel of the boxes did not match the original
> > > sequence and did not look close enough after that.
> > >
> > > Anyways, I guess here's how I would approach this:
> > >
> > > reps=: 1+0,~0,2~:/\[:[^:(0~:[)/\.@:*2 -/\]
> > > ud=: reps ((1,2 =/\ [ # #\@]) <;.1 #) ]
> > >
> > > Thanks,
> > >
> > > --
> > > Raul
> > >
> > > On Thu, May 20, 2021 at 10:42 AM R.E. Boss <r.e.b...@outlook.com> wrote:
> > > >
> > > > I thought it was clear from the output (therefore I used ?. in the
> > > > testcases) that the order of the input array should not be altered.
> > > > That was the constraint you were missing.
> > > >
> > > >
> > > > R.E. Boss
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: Programming <programming-boun...@forums.jsoftware.com> On
> > > > Behalf Of Raul Miller
> > > > Sent: donderdag 20 mei 2021 16:33
> > > > To: Programming forum <programm...@jsoftware.com>
> > > > Subject: Re: [Jprogramming] ups & downs
> > > >
> > > > I could use some additional details.
> > > >
> > > > I mean... it seems to me that Foo=:<@/:~ would minimally satisfy the
> > > > requirements which have been stated so far.
> > > >
> > > > But, presumably, there's some kind of "cost function" which we are
> > > > trying to minimize, and presumably that has something to do with how
> > > > pairs are handled?
> > > >
> > > > Or, perhaps, you have a constraint that no more than three of any given
> > > > number may appear in any box, and I think I see a constraint that
> > > > adjacent boxes must alternate their order. But perhaps there are also
> > > > similar additional metrics or constraints?
> > > >
> > > > Thanks,
> > > >
> > > > --
> > > > Raul
> > > >
> > > > On Thu, May 20, 2021 at 6:43 AM R.E. Boss <r.e.b...@outlook.com> wrote:
> > > > >
> > > > > Given an array of numbers, like
> > > > >
> > > > > ?.@#~20
> > > > > 14 16 8 6 5 8 6 16 16 19 13 12 3 1 9 12 17 0 9 5
> > > > >
> > > > > there is always a sequence of (non-strict) ups & downs, like
> > > > >
> > > > > 14 16;16 8 6 5;5 8;8 6;6 16 16 19;19 13 12 3 1; 1 9 12 17;17
> > > > > 0;0
> > > > > 9;9 5
> > > > > +-----+--------+---+---+----------+------------+---------+----+---+---+
> > > > > |14 16|16 8 6 5|5 8|8 6|6 16 16 19|19 13 12 3 1|1 9 12 17|17 0|0
> > > > > |9|9
> > > > > |5|
> > > > > +-----+--------+---+---+----------+------------+---------+----+---+---+
> > > > >
> > > > > Well, this is the way I prefer to have the ups & downs, where they
> > > > > share their border terms.
> > > > > Which verb makes this transformation?
> > > > > Elegance, as always, is appreciated, correctness is a must,
> > > > > efficiency a blessing.
> > > > >
> > > > > Some testcases:
> > > > >
> > > > > Foo ?.@#~25
> > > > > +----+---+---+-------+-----+-----+----+---+---+----+-------+----+----+-------+----+----+----+----+------+---+
> > > > > |19 6|6 8|8 6|6 10 23|23 16|16 21|21 1|1 9|9 8|8 22|22 13 1|1
> > > > > |14|14
> > > > > |2|2 17 20|20 9|9 15|15 7|7 22|22 4 2|2 9|
> > > > > +----+---+---+-------+-----+-----+----+---+---+----+-------+----+----+-------+----+----+----+----+------+---+
> > > > > Foo ?.@#~30
> > > > > +--------+------+----+--------+--------+---------+----+-----+-----+----+----+-----+-----+----+-------+-------+-------+--------+-----+-----+
> > > > > |24 26 28|28 6 5|5 28|28 16 16|16 16 26|26 19 3 2|2 13|13 11|11
> > > > > |19|19
> > > > > |2|2 27|27 10|10 19|19 5|5 17 27|27 19 7|7 24 28|28 27 14|14 22|22
> > > > > |2|21|
> > > > > +--------+------+----+--------+--------+---------+----+-----+-----+----+----+-----+-----+----+-------+-------+-------+--------+-----+-----+
> > > > >
> > > > >
> > > > > R.E. Boss
> > > > > ------------------------------------------------------------------
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