longest increacing subsequence

lis.hs

--import Data.List
--import Debug.Trace

--dat=[1,3,5,0,2,4]
--dat=[10,9,8,7,6,5]
--dat=[39,88,67,5,69,87,82,64,58,61]
dat=[2,1,4,3,6,5,8,7,10,9,12,11,14,13,16,15,18,17,20,19,22,21,24,23,26,25,28,27,30,29,32,31,34,33,36,35,38,37,40,39,42,41,44,43,46,45,48,47,50,49]
--dat=[10,20,11,12]

--tr v = trace (show v) v
less x y = x < y


score::[(Int,(Int,Int))]->(Int,Int)
score f = 
  let m'= maximum $ map (fst.snd) f
      m''= sum $ map (snd.snd) $ filter (\v-> m' == (fst.snd) v) f
  in (m',m'')
  
  
lis :: [Int]->[(Int,Int)]
lis []=[]
lis (x:xs)=
  let xs'::[(Int,Int)]
      xs'= lis xs
      f::[(Int,(Int,Int))]
      f = filter (\(a,_)->x < a) $ zip xs xs'
      (m',m'') =score f
  in case f of 
    [] -> (1,1)      : xs'
    _  -> (m'+1,m'') : xs'

main=do
  print $ score $ zip dat $ lis dat
  return ()