Codility TapeEquilibrium (https://codility.com/demo/results/demo8HMGGH-TPP/)

CodilityTapeEquilibrium.scala

import scala.math.{min, abs}

object Solution {
    def solution(A: Array[Int]): Int = {
      if (A.size < 2 || A.size > 100000) sys.error(s"Invalid input - array size: ${A.size}")

      val total = A.map(_.toLong).sum

      (A.foldLeft[(Int, Long, Long)](-1, -1, 0l) { (t, i) =>
        if (i < -1000 || i > 1000) sys.error(s"Invalid array element: $i")

        val (x, currentMin, lastLeftSum) = t
        val index = x + 1

        (index + 1 == A.size) match {
          case true =>
            // Do nothing on the last element
            t

          case false =>
            val leftSum = lastLeftSum.toLong + A(index).toLong
            val rightSum = total - leftSum

            val thisMin = abs(leftSum- rightSum)
            val results = if (currentMin == -1) thisMin
            else min(currentMin, thisMin)

            (index, results, leftSum)
        }

      })._2.toInt
    }
}