Tom Pledger
We've seen some nice concise solutions that can deal with the original problem: solve 1505 [215, 275, 335, 355, 420, 580] I'll be a nuisance and bring up this case: solve 150005 [2, 4, 150001]
Here's my solution to the xkcd problem (yay infinite lists): xkcd_c287' = foldr (\cost without -> let (poor, rich) = splitAt cost without with = poor ++ zipWith (++) rich (map (map (cost:)) with) in with) ([[]] : repeat []) [215, 275, 335, 355, 420, 580] -- [2, 4, 150001] !! 1505 -- 150005 Replacing the two lines with comments by the comments solves your case quickly. Thanks! That was fun! -- Edit this signature at http://www.digitas.harvard.edu/cgi-bin/ken/sig http://www.unaids.org/en/HIV_data/epi2006/ UNAIDS/WHO AIDS Epidemic Update: December 2006