Where do you get the requirement that the numbers must be unique?

The problem stated here was:

"How many distinct triplets have a sum of 1,000,000 (provided all numbers
are integers and are positive)?"

The quora statement of the issue is slightly different, but
substantially the same:

"How many distinct unordered triplets of positive integers have a sum
of 1,000,000?"

No occurrences of "unique integers" anywhere that I can see... just a
requirement that each triplet be considered unique (and that the order
of the integers within a triplet is irrelevant).

Thanks,

-- 
Raul

On Sun, May 20, 2018 at 7:59 PM, Don Guinn <dongu...@gmail.com> wrote:
> Yes, I had a bug in my previous definition for triplescount. Stupid. Should
> have checked more before speaking.
>
> But As I understand the problem, the numbers in each triple should be
> unique. Looking at has several triples with duplicate numbers.
>
>    t #~ 3=#&>t
> +-----+-----+-----+-----+-----+-----+-----+-----+
> |8 1 1|7 2 1|6 3 1|6 2 2|5 4 1|5 3 2|4 4 2|4 3 3|
> +-----+-----+-----+-----+-----+-----+-----+-----+
>
> The values (8 1 1; 6 2 2; 4 4 2; 4 3 3) are not unique leaving
>    7 2 1; 6 3 1;5 4 1;5 3 2
> +-----+-----+-----+-----+
> |7 2 1|6 3 1|5 4 1|5 3 2|
> +-----+-----+-----+-----+
>
> which is what I get in the triples definition below. Same except the order
> in each row is reversed.
>
>    triples 10
> 1 2 7
> 1 3 6
> 1 4 5
> 2 3 5
>
> I rewrote triplescount and made a triples as follows. This time I followed
> my logic in my previous e-mail which I didn't in the definition of
> triplescount then:
>
> triples=:3 : 0
> n1max=.<:<.y%3
> n1=.>:i.n1max
> n2max=.<:>.-:y-n1
> n2=.n1+&.>(<@:>:@i.)"0 n2max-n1
> n1n2=.;(<"0 n1),.&.>n2
> n1n2,.y-+/"1 n1n2
> )
>
> triplescount=:3 : 0
> n1max=.<:<.y%3
> n1=.>:i.n1max
> n2max=.<:>.-:y-n1
> +/n2max-n1
> )
>
>    triples &.>6+i.10
> +-----+-----+-----+-----+-----+-----+-----+------+------+------+
> |1 2 3|1 2 4|1 2 5|1 2 6|1 2 7|1 2 8|1 2 9|1 2 10|1 2 11|1 2 12|
> |     |     |1 3 4|1 3 5|1 3 6|1 3 7|1 3 8|1 3  9|1 3 10|1 3 11|
> |     |     |     |2 3 4|1 4 5|1 4 6|1 4 7|1 4  8|1 4  9|1 4 10|
> |     |     |     |     |2 3 5|2 3 6|1 5 6|1 5  7|1 5  8|1 5  9|
> |     |     |     |     |     |2 4 5|2 3 7|2 3  8|1 6  7|1 6  8|
> |     |     |     |     |     |     |2 4 6|2 4  7|2 3  9|2 3 10|
> |     |     |     |     |     |     |3 4 5|2 5  6|2 4  8|2 4  9|
> |     |     |     |     |     |     |     |3 4  6|2 5  7|2 5  8|
> |     |     |     |     |     |     |     |      |3 4  7|2 6  7|
> |     |     |     |     |     |     |     |      |3 5  6|3 4  8|
> |     |     |     |     |     |     |     |      |      |3 5  7|
> |     |     |     |     |     |     |     |      |      |4 5  6|
> +-----+-----+-----+-----+-----+-----+-----+------+------+------+
>    triplescount &>6+i.10
> 1 1 2 3 4 5 7 8 10 12
>    (#@:triples) &>6+i.10
> 1 1 2 3 4 5 7 8 10 12
>
> The results above look right. Please correct me if I'm wrong.
>
> Below tried several triplescount's and see a pattern, but a little
> different from what others are getting.
>
>    triplescount"0] 10^>:i.7x
> 4 784 82834 8328334 833283334 83332833334 8333328333334
>
> Well, this has been fun.
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm

Reply via email to