使用具有自定义数据类型的二叉搜索树？

Question

我创建了一个二叉搜索树：

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

insertTreeElements :: (Ord a) => a -> SearchTree a -> SearchTree a --Create    binary tree input method
insertTreeElements x Empty = Node x Empty Empty
insertTreeElements x (Node a left right)
   | x == a     = Node x left right
   | x < a  = Node a (insertTreeElements x left) right
   | x > a      = Node a left (insertTreeElements x right)

makeTree :: (Ord a) => (a -> SearchTree a -> SearchTree a) -> SearchTree a -> [a] -> SearchTree a --Create binary tree
makeTree iTE Empty li = foldr iTE Empty li

我正在尝试传递以下列表：

Type Age = Int
mylist = [Age 12, Age 100, Age 2, Age 3, Age 43]

但是输出不正确，它不会根据年龄的大小对树进行排序？如何编辑insertTreeElements以允许它与'Age x'一起使用？

Answer 1

可能你遇到的最大问题是：

   | x > a      = Node a left (insertTreeElements x left)

请注意，您写了left两次 - 大概其中一个应该是right。