Hi, I have problems with assignation of types, I did this ... ***** End: -- Codigo de Huffman The rest of the message is ignored:
-- -- -- Un arbol binario comun -- data BinTree a = Hoja a | Nodo (BinTree a) (BinTree a)
type Huff = BinTree Char
-- Arbol especifico para la funcion `combinar' -- data Tree = Leaf Int Char | Node Int Tree Tree
-- Binary search tree para la funcion `freqs' -- data BSTree a = Nil | BSNode a (BSTree a) (BSTree a)
-- Calculo de las frequencias de cada letra -- freq :: BSTree (Char,Int) -> String -> BSTree (Char,Int) freq t [] = t freq t (x:xs) = insertTree x (freq t xs)
insertTree :: Char -> BSTree (Char,Int) -> BSTree (Char,Int) insertTree x Nil = BSNode (x,1) Nil Nil insertTree x (BSNode (c,n) t1 t2) | x==c = BSNode (c,n+1) t1 t2 | x<c = BSNode (c,n) (insertTree x t1) t2 | x>c = BSNode (c,n) t1 (insertTree x t2)
flatten :: BSTree a -> [a] flatten Nil = [] flatten (BSNode x t1 t2) = [x] ++ (flatten t1) ++ (flatten t2)
iSort :: [(Char,Int)] -> [(Char,Int)] iSort [] = [] iSort (x:xs) = ins x (iSort xs)
ins :: (Char,Int) -> [(Char,Int)] -> [(Char,Int)] ins a [] = [a] ins a@(c,n) l@((d,m):xs) | n<=m = a:l | otherwise = (d,m):ins a xs
freqs :: String -> [(Char,Int)] freqs xs = (iSort . flatten) (freq Nil xs)
-- Decodificacion -- decodificar :: [Int] -> Huff -> String decodificar xs t = aux xs t t where aux [] (Hoja c) t = [c] aux (x:xs) (Hoja c) t = [c] ++ aux (x:xs) t t aux (0:xs) (Nodo t1 t2) t = aux xs t1 t aux (1:xs) (Nodo t1 t2) t = aux xs t2 t
-- Codificacion respecto a un arbol dado -- cod :: Char -> Huff -> [Int] cod c t = head (aux c t) where aux c (Hoja d) | c==d = [[]] | otherwise = [] aux c (Nodo t1 t2) = [ (0:xs) | xs <- aux c t1 ] ++ [ (1:xs) | xs <- aux c t2 ]
codificar :: String -> Huff -> [Int] codificar xs t = concat (map (\c->cod c t) xs)
--Construccion del arbol de Huffman -- combinar :: [Tree] -> [Tree] combinar [t] = [t] combinar (t1:t2:ts) = insert (Node (w1+w2) t1 t2) ts where weight (Leaf n x) = n weight (Node n _ _) = n insert t [] = [t] insert t (u:us) | weight t < weight u = t:u:us | otherwise = u:(insert t us) w1 = weight t1 w2 = weight t2
combinarTodos :: [Tree] -> Tree combinarTodos [t] = t combinarTodos ts = combinarTodos (combinar ts)
-- Pegamos la construccion del arbol y la codificacion del texto -- codificarTexto :: String -> ([Int], Huff) codificarTexto xs = (ys, t) where ls = freqs xs desmarcar (Leaf n x) = Hoja x desmarcar (Node n t1 t2) = Nodo (desmarcar t1) (desmarcar t2) t = (desmarcar . combinarTodos) (map (\(c,n)->Leaf n c) ls) ys = codificar xs t
-- Example -- prueba1 = let (s, t) = codificarTexto "Salvete, omnes" in decodificar s t
"Please, I need help.
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