Tree Map

package tree

object Map {

  def map[A, B](t: Tree[A])(f: A => B): Tree[B] = t match {
    case Leaf(a)      => Leaf(f(a))
    case Branch(l, r) => Branch(map(l)(f), map(r)(f))
  }

  def main(args: Array[String]): Unit = {
    val tree = Branch(Leaf(1), Branch(Branch(Branch(Leaf(3), Branch(Leaf(5), Leaf(6))), Leaf(4)), Leaf(2)))
    println(map(tree)(_ * 2))
  }

}

Branch(Leaf(2),Branch(Branch(Branch(Leaf(6),Branch(Leaf(10),Leaf(12))),Leaf(8)),Leaf(4)))