aparler/RosettaCodeData
1
0
Fork 0
Code Issues 12 Pull requests 3 Projects Releases Packages Wiki Activity Actions

June 2018 Update

Browse source
This commit is contained in:
Ingy döt Net 2018-06-22 20:57:24 +00:00
parent ba8067c3b7
commit 22f33d4004
5278 changed files with 84726 additions and 14379 deletions
Download patch file Download diff file Expand all files Collapse all files

15
Task/Hailstone-sequence/Haskell/hailstone-sequence-1.hs
View file

@ -1,20 +1,21 @@
import Data.List (maximumBy)
import Data.Ord (comparing)
collatz :: Int -> Int
collatz n
| even n = n `div` 2
| otherwise = 3 * n + 1
hailstone :: Int -> [Int]
hailstone = takeWhile (/= 1) . iterate collatz
where
collatz n =
if even n
then n `div` 2
else 3 * n + 1
longestChain :: Int
longestChain =
fst
(maximumBy (comparing snd) (((,) <*> length . hailstone) <$> [1 .. 100000]))
fst $
maximumBy (comparing snd) $ (,) <*> (length . hailstone) <$> [1 .. 100000]
--TEST -------------------------------------------------------------------------
main :: IO ()
main =
mapM_
putStrLn