result

true
Execution n = 1007377 in 1521 ms

true
Tuning Execution n = 1007377 in 1394 ms

TwoSum.scala

object TwoSum {

  def sum(n: Int, sorted: ArrayBuffer[Int]): Boolean = sorted.par.find(x => isMatch(x, n, sorted)).isDefined

  def isMatch(x: Int, n: Int, sorted: ArrayBuffer[Int]): Boolean = sorted.find( y => (x + y) == n).isDefined

}

TwoSumTuning.scala

object TwoSumTuning {

  def sum(n: Int, sorted: ArrayBuffer[Int]): Boolean = sorted.par.find(x => isMatch(x, n, sorted)).isDefined

  def isMatch(x: Int, n: Int, sorted: ArrayBuffer[Int]): Boolean = {
    var result = false
    breakable {
      var a = 0
      for (a <- x until sorted.size) {
        if ((x + sorted(a)) == n) {
          result = true
          break
        }
      }
    }
    return result
  }
}