DouKaku?

import System.Environment
import System.Random

main :: IO ()
main = do { (p:q:_) <- getArgs
          ; let (n,m) = (read p,read q)
          ; newStdGen >>= loop n m [1..n] >>= print
          }

loop _ 0 _ _ = return []
loop n m s g 
 = case randomR (0,n-1) g of
    (n',g') -> case splitAt n' s of
                (xs,y:ys) -> loop (n-1) (m-1) (xs++ys) g' >>= return . (y:)