Lowest common ancestor. One of a very common binary tree puzzle. The implementation in scala is in about 10 lines

Tree.scala

/**
  * Lowest common ancestor. One of a very common binary tree puzzle. The implementation in scala is in about 10 lines
  */
object Tree {
  def findLCA(tree: Tree, x: Int, y: Int): Option[Tree] = {
    if (tree.value == x || tree.value == y) Some(tree)
    else (if (tree.left != None) findLCA(tree.left.get, x, y) else None, if (tree.right != None) findLCA(tree.right.get, x, y) else None) match {
      case (Some(r), Some(l)) => Some(tree)
      case (Some(r), None) => Some(r)
      case (None, Some(l)) => Some(l)
      case (None, None) => None
    }
  }
}

case class Tree(value: Int, left: Option[Tree], right: Option[Tree])