Build some functions

This project is really easy. I've already done it. Here are the first two functions, and the output of main: subst :: Eq t => t -> t -> [t] -> [t] subst pat rep l = go l [] where go [] acc = acc go (x:xs) acc = v : go xs acc where v = if x == pat then rep else x interleave :: [t] -> [t] -> [t] interleave a b = go a b [] False where go [] l2 acc _ = acc ++ l2 go l1 [] acc _ = acc ++ l1 go (x:xs) (y:ys) acc False = x : go xs (y:ys) acc True go (x:xs) (y:ys) acc True = y : go (x:xs) ys acc False main = do print $ subst 0 1 [0,1,2,3] print $ subst 'e' 'o' "dog" print $ subst 'e' 'o' "elephant" print $ interleave [1,2,3,4] [11,12,13,14] print $ interleave "" "dog" print $ interleave "wl" "arus" print $ interleave "tlpone" "eeh" print $ unroll 3 [1,2,3,4,5] print $ unroll 8 [1,2,3] print $ unroll 4 "ski" ------------------------------------------ [1,1,2,3] "dog" "olophant" [1,11,2,12,3,13,4,14] "dog" "walrus" "telephone" [1,2,3] [1,2,3,1,2,3,1,2] "skis"