Another update from ingydotnet^djgoku

Task/Hailstone-sequence/Haskell/hailstone-sequence-1.hs

@@ -0,0 +1,18 @@
+import Data.List (maximumBy)
+import Data.Ord (comparing)
+
+main = do putStrLn $ "Collatz sequence for 27: "
+            ++ ((show.hailstone) 27)
+            ++ "\n"
+            ++ "The number "
+            ++ (show longestChain)
+            ++" has the longest hailstone sequence"
+            ++" for any number less then 100000. "
+            ++"The sequence has length "
+            ++ (show.length.hailstone $ longestChain)
+
+hailstone = takeWhile (/=1) . (iterate collatz)
+  where collatz n = if even n then n `div` 2 else 3*n+1
+
+longestChain = fst $ maximumBy (comparing snd) $
+               map ((\x -> (x,(length.hailstone) x))) [1..100000]