Kangyuan Niu niuk
niuk
/ gist:0387a0694826178c17dd
Last active
August 29, 2015 14:20
— forked from anonymous/gist:f7fd4013fe3c13e88279
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| data Op = Plus | Minus | Concat deriving Show | |
| f l = concatMap (\r -> map (: r) l) | |
| step :: Int -> Op -> (Int, Int) -> (Int, Int) | |
| step digit op (carry, sum) = case op of | |
| Concat -> (digit * 10 ^ ceiling (logBase 10 (fromIntegral carry)) + carry, sum) | |
| Plus -> (digit, sum + carry) | |
| Minus -> (digit, sum - carry) |