tree.hs

data Tree a = Leaf | Node (Tree a) a (Tree a) deriving (Show, Eq)

treeTest :: Tree Integer
treeTest = Node (Node Leaf 5 (Node Leaf 4 Leaf)) 10 (Node Leaf 20 (Node Leaf 50 (Node Leaf 100 Leaf)))

treeSum :: Tree Integer -> Integer
treeSum tree | tree == Leaf = error "Empty tree!"
             | otherwise  = helper 0 tree where 
    helper acc (Node f d s) | (f == Leaf && s == Leaf) = acc + d
                            | (f /= Leaf && s /= Leaf) = (helper (acc + d) f) + (helper acc s)
                            | (f/=Leaf) = helper (acc + d) f
                            | (s /= Leaf) = helper (acc + d) s

treeHeight :: (Eq t1, Ord t, Num t) => Tree t1 -> t
treeHeight tree | tree == Leaf = 0
                | otherwise = helper 0 tree where 
    helper acc (Node f _ s) | (f /= Leaf && s /= Leaf) = 
            
            let {fHeight = (helper (acc + 1) f); sHeight = (helper (acc + 1) s)}                                        
            in  if fHeight >=  sHeight then fHeight else sHeight                                                                   
                            
                            | f/=Leaf = helper (acc + 1) f
                            | s /= Leaf = helper (acc + 1) s
                            | otherwise = acc + 1