Scala Quick Find and Quick Union implementations

Main.scala

import scala.annotation.tailrec

object Main extends App {

  def QuickFindExample() {
    var qu = QuickFind(10)
    qu.union(1, 6)
    qu.union(2, 6)
    qu.union(2, 7)

    println("Connected (2,6): " + qu.connected(2, 6))
    println("Connected (2,7): " + qu.connected(2, 7))
    println("Connected (1,6): " + qu.connected(1, 6))
    println("Connected (1,8): " + qu.connected(1,8))
  }

  def QuickUnionExample() {
    var qu = QuickUnion(10)
    qu.union(1, 6)
    qu.union(2, 6)
    qu.union(2, 7)

    println("Connected (2,6): " + qu.connected(2, 6))
    println("Connected (2,7): " + qu.connected(2, 7))
    println("Connected (1,6): " + qu.connected(1, 6))
    println("Connected (1,8): " + qu.connected(1,8))
  }

  QuickFindExample()
  QuickUnionExample()
}

trait UnionFind {
  def union(destination: Int, source: Int): Unit;

  def connected(a: Int, b: Int): Boolean;
}

case class QuickFind(val size: Int) extends UnionFind {

  private val items = new Array[Int](size)

  items.indices.foreach(x => {
    items(x) = x
  })

  def union(destination: Int, source: Int): Unit = {
    val itematdest = items(destination)
    val itematsource = items(source)

    if (itematdest == itematsource)
      return

    items.zipWithIndex.foreach(x => {
      if (x._1 == itematsource)
        items(x._2) = itematdest

    })
  }

  def connected(a: Int, b: Int): Boolean = ((items(a)).equals(items(b)))
}

case class QuickUnion(val size: Int) extends UnionFind {

  private val items = new Array[Int](size)

  items.indices.foreach(x => {
    items(x) = x
  })

  def union(destination: Int, source: Int): Unit = {
    val itematdest = items(destination)
    val itematsource = items(source)
    val rootdest = root(itematdest)
    val rootsource = root(itematsource)

    if (rootdest != rootsource)
      items(rootsource) = rootdest

  }

  @tailrec
  private def root(component: Int) : Int = {
    val item = items(component)

    if(item == component)
      component
    else
      root(item)
  }

  def connected(a: Int, b: Int): Boolean = ((root(items(a))).equals(root(items(b))))
}