Discussion on: Java Daily Coding Problem #008

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

isUnival :: (Eq a) => Tree a -> Bool
isUnival tree = case tree of
  Empty -> False
  Node v l r -> case (l, r) of
    (Node lv _ _, Node rv _ _) -> v == lv && v == rv && isUnival l && isUnival r
    (Node lv _ _, Empty) -> v == lv && isUnival l
    (Empty, Node rv _ _) -> v == rv && isUnival r
    (Empty, Empty) -> True

univalCount :: (Eq a) => Tree a -> Int
univalCount tree = case tree of
  Empty -> 0
  Node _ l r -> if isUnival tree then 1 + childCount else childCount
    where
      childCount = univalCount l + univalCount r