Nicest. I think your definition has reached nirvana. I think a good haskell-cafe thread is like a Shakespeare play. People at every level of experience can get something from it. The early replies answer the question, with follow-on ones exploring the roads less traveled. I for one did not know how to construct the fully pointless version below, and if I hadn't asked, I doubt I ever would. I also learned of the list monad this exact same way, so I think its a good and gentle way to introduce people to it. Dan Bjorn Bringert wrote:
On Jul 18, 2007, at 1:00 , Dan Weston wrote:
Bjorn Bringert wrote:
import Data.List maxsubarrays xs = maximumBy (compare `on` sum) [zs | ys <- inits xs, zs <- tails ys]
I love this solution: simple, understandable, elegant.
As a nit, I might take out the ys and zs names, which obscure the fact that there is a hidden symmetry in the problem:
maxsubarrays xs = pickBest (return xs >>= inits >>= tails) where pickBest = maximumBy (compare `on` sum) -- NOTE: Since pickBest is invariant under permutation of its arg, -- the order of inits and tails above may be reversed.
Dan Weston
Nice. Here's a pointless version:
maxsubarrays = maximumBy (compare `on` sum) . (>>= tails) . inits
Though I avoided using the list monad in the first solution, since I thought it would make the code less understandable for a beginner.
/Björn