Suchbäume: Herstellen

aus (ungeordneter) Liste herstellen:

import Data.List (partition)

make :: [ Int ] -> Tree Int
make []       = Leaf
make (x : xs) =
   let ( low, high ) = partition ( < x ) xs
   in  Node { key   = x
            , left  = make low
            , right = make high
            }