It works fine for me, whether compiled or interpretted. Are you sure
there isn't some residual files left from a previous compile that you
are running? Try rm *.o *.hi. Or something more mundane, not saving
the file, or running the wrong executable.
2012/1/14 Artur Tadrała
Hello
While learning Haskell I'm trying to solve some simple problems on spoj.pl occasionally. Currently I'm working on: http://www.spoj.pl/problems/BWHEELER/. I figured out how to solve it but I have some problems with reading input (that's my guess)
Here is my solution:
import Data.List import Data.Array import qualified Data.ByteString.Lazy.Char8 as BS import IO
traverse :: Array Int (Char, Int) -> Int -> Int -> String -> String traverse endings n k acc = let (c,i) = endings ! n in if k == 0 then acc else traverse endings i (k-1) (c:acc)
solve :: (Int, String) -> String solve (n,w) = let l = length w endings = sort $ zip w [0..] endingsArray = array (0, l) (zip [0..] endings) in reverse $ traverse endingsArray (n-1) l ""
parseCases :: [BS.ByteString] -> [(Int, String)] parseCases (l:l':ls) = let n = readInt l w = BS.unpack l' in (n,w):parseCases ls parseCases _ = []
main :: IO () main = do ls <- BS.lines `fmap` (BS.readFile "input.txt") --BS.getContents putStr $ unlines $ map solve $ parseCases ls
readInt :: BS.ByteString -> Int readInt x = case BS.readInt x of Just (i,_) -> i Nothing -> error ("Unparsable Int" ++ (show x))
The input.txt file contains following text: 2 bacab 3 rwlb 11 baaabaaaabbbaba 0
When I compile and execute this code i get follwing output: aaaaaa lllll bbb
It's different when compared to this in ghci ( this is what I expect): > map solve [(2,"bacab"), (3, "rwlb"), (11,"baaabaaaabbbaba")] ["abcba","rbwl","baaabbbbaaaaaab"]
Can you explain me what I'm doing wrong? I appreciate any tips how to improve this code also.
Thanks for help! Artur Tadrała
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