Background: http://xkcd.com/c287.html
(That's not really an np-complete problem, near as I can tell.)
Given
ap=:2.15 2.75 3.35 3.55 4.2 5.8
This will list distinct combinations of ap which total to 15.05:
~./:~&.>(#~15.05=+/&>)(#~15.05>:+/\)&.>,{7#<ap
But, that's not very efficient.
A more efficient approach might be
15.05 order ap
where:
order=:4 :0
min=.<./y
pos=.,:y
r=.''
while.{:$pos=.pos#"1~x>:min++/pos do.
pos=.(#"1~ <:/@(_2{.])) pos((#"1~#), {:@[EMAIL PROTECTED] ,@# ,:@]) y
r=.r,<"1|:pos#"1~x=+/pos
end.
/:~r
)
But, maybe that could be more elegant.
Does anyone have any good suggestions?
(Does J's library have any built-ins for addressing this kind
of problem?)
Thanks,
--
Raul
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