おためし,はてな記法
見出しだぞい
コードの埋め込み(Haskell)
collatz :: Integer -> Maybe Integer collatz n = helper n 0 where helper :: Integer -> Integer -> Maybe Integer helper n count | n == 0 || n < 0 = Nothing | n == 1 = Just count | even n = helper (div n 2) (count + 1) | otherwise = helper ((3*n) + 1) (count + 1)
なるほどな.