diff options
Diffstat (limited to 'challenge-059/stuart-little/haskell/ch-2.hs')
| -rwxr-xr-x | challenge-059/stuart-little/haskell/ch-2.hs | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/challenge-059/stuart-little/haskell/ch-2.hs b/challenge-059/stuart-little/haskell/ch-2.hs new file mode 100755 index 0000000000..1269923da7 --- /dev/null +++ b/challenge-059/stuart-little/haskell/ch-2.hs @@ -0,0 +1,17 @@ +#!/usr/bin/env runghc + +-- run <script> <space-separated numbers> + +import System.Environment (getArgs,) +import Control.Monad (liftM,) +import Data.Digits (digitsRev,) +import Data.List (transpose,) +import Data.List.Utils (countElem,) + +diffs :: Int -> [Int] -> Int +diffs l xs = let (zeros,ones,lxs) = (countElem 0 xs,countElem 1 xs,length xs) in + div (l*(l-1) - ones*(ones - 1) - (zeros + l - lxs)*(zeros+l - lxs - 1)) 2 + +main = do + nrs <- liftM (map (read::String->Int)) getArgs + print $ sum $ map (diffs $ length nrs) $ transpose $ map (digitsRev 2) nrs |
