Scala sum binary Tree

Question

I saw anwser here but i dont have Object Empty and i have leaf not just everthing in Node like this : case class Node ( val e : Int ,left : BinaryTree, right : BinaryTree).

I have problem with adding Leaf as param in this def sums.

import scala.annotation.tailrec
 /**
 * @author emil
 */
 class tree {


 }


 sealed abstract class BinaryTree
 case class Node (left : BinaryTree, right : BinaryTree) extends BinaryTree
 case class Leaf (value : Int) extends BinaryTree


 object Main {
   def main(args : Array[String]) {
     val tree = Node(Node(Leaf(1),Leaf(3)), Node(Leaf(5),Leaf(7)));

     println(tree)

  sum(tree)

   }
  def sum(bin: BinaryTree) = {
  def sums(trees: List[BinaryTree], acc: Int): Int = trees match {
    case Nil => acc
    case Node(l, r) :: rs => sums(l :: r :: rs,  acc)
  }

  sums(List(bin),0)
}


}

Facundo Fabre · Accepted Answer · 2015-01-27 13:35:02Z

1

If I understand what you want to do is something like

case Leaf(v) :: rs => sums(xs, acc+v)

answered Jan 27, 2015 at 13:35

Facundo Fabre

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1 Comment

Wiktor Dębski Over a year ago

ye i just achieve this 5 minutes ago :D But thanks for anwser

user5102379 · Accepted Answer · 2015-01-27 13:44:09Z

0

May be:

  def sum(bin: BinaryTree) = {
    def sums(t: BinaryTree): Int = t match {
      case Leaf(v)    => v
      case Node(l, r) => sums(l) + sums(r)
    }

    sums(bin)
  }

  val res = sum(tree)
  println(res) // 16

answered Jan 27, 2015 at 13:44

user5102379

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