Skip, you can probably put together a tacit version using {.@[ for x(0) , {:@[
for x(1), and the equivalence of g and h below, described in the second page of
the vocabulary entry for Power ^:
http://www.jsoftware.com/docs/help701/dictionary/d202v.htm
g=: u ^: p ^: _
h=: 3 : 't=. y while. p t do. t=. u t end.'
--But when you have finished, you may prefer your explicit version!
Kip Murray
Sent from my iPad
On May 3, 2013, at 2:41 AM, Skip Cave <[email protected]> wrote:
> A generalized version of the Josephus problem would be to allow any skip
> number, and any number of survivors. This would require three variables
> input to the verb.
>
> 1. The number of people in the line (n)
> 2. The number skipped for each step (s)
> 3. The number of people left to go free at the end (r)
>
> Given these three integers, what positions will be left at the end of the
> process?
>
> usage: s r jose n
> where s = the number skipped, r = the number remaining, and n = the number
> in line.
>
> Here's an explicit function to solve the problem:
>
> jose=: 4 : 0
> f =. i.0 NB. Initialize output vector
> s =. <:0{x NB. x(0) is the skip number
> r =. 1{x NB. x(1) is the number left
> I =. y NB. y is the total positions
> L =. 1+i. y NB. L is the position list
> whilst. I =. I-1 do.
> L =. s |. L
> f =. f, {. L
> L =. }. L
> end.
> (r-y) {. f NB. Take the last r positions
> )
>
> Examples:
>
> 3 4 jose 20 NB. Skip 3, leave 4, out of 20
> 8 2 13 20
>
> 5 1 jose 200 NB. Skip 5, leave 1, out of 200
> 113
>
> I have been trying to make this tacit, but no luck so far. I'm still pretty
> much of a novice with tacit functionality.
>
> Skip
>
> --
> Skip Cave
> Cave Consulting LLC
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
