9/one.icl

   1 module one
   2
   3 import StdEnv
   4 import Data.List
   5 import StdMaybe
   6
   7 read :: *File -> [Int]
   8 read f
   9         # (ok, i, f) = freadi f
  10         | not ok = []
  11         = [i:read f]
  12
  13 Start w
  14         # (io, w) = stdio w
  15         # ls = read io
  16         = (one ls, two ls)
  17
  18 one = last o pre
  19
  20 pre l
  21         # (preamble, [num:rest]) = splitAt 25 l
  22         | isEmpty [()\\a<-preamble, b<-preamble | a + b == num] = [num]
  23         = [num:pre (tl l)]
  24
  25 two ls
  26         # ls = fst (splitAt 25 ls) ++ pre ls
  27         # a = sort (hd (calc (last ls) ls))
  28         = (last a + hd a)
  29 where
  30 //      calc :: Int [Int] -> (Int, Int)
  31         calc num xs = hd (filter (not o isEmpty) [calc` num l\\l<-tails xs])
  32
  33         calc` num xs = filter ((==)num o sum) (dropWhile ((<) num o sum) (inits xs))