repmin.hs

data Tree = Leaf Int
          | Node Tree Tree deriving Show


repmin t = tr
  where (mn, tr) = walk mn t


walk mn (Leaf n)     = (n, Leaf mn)
walk mn (Node t1 t2) = (n1 `min` n2, Node tr1 tr2)
    where
    (n1, tr1) = walk mn t1
    (n2, tr2) = walk mn t2

t = Node (Node (Leaf 10) (Leaf 5)) (Node (Leaf 2) (Node (Leaf 0) (Leaf 10)))
vmintree = repmin t