build and walk through the tree

tree.scala

case class Tree(var left: Tree, var right: Tree, var value: Int)

def build(seq: Seq[Int]): Tree = seq match {
  case Nil => null
  case _ =>
    import scala.util.Random
    val pos = Random nextInt seq.length
    val (left, right) = seq splitAt pos
    Tree(build(left), build(right.tail), right.head)
}

def walk(tree: Tree) {
  if (tree != null) {
    walk(tree.left)
    println(tree.value)
    walk(tree.right)
  }
}