Codility10Peaks.scala

  val input = Array(1,2,3,4,3,4,1,2,3,4,6,2)

  println(evaluate(input))

  def evaluate(arr: Array[Int]): Int = {
    val p = peaks(arr)
    var i = arr.length
    while (i > 0) {
      if (arr.length % i == 0
          && canSplit(arr.length, p , arr.length/i)) {
        return i
      }
      i -= 1
    }
    0
  }

  def canSplit(arrLength: Int,
               peaks: IndexedSeq[Int],
               numberOfChunks: Int): Boolean = {

    // checks if we can split into numberOfChunks chunks
    def aux(currentChunkIndex: Int, peakIndex: Int): Boolean = {
      val endOfChunk = currentChunkIndex + numberOfChunks

      if (currentChunkIndex == arrLength) true
      else if (peakIndex == peaks.length) false
      else {
        if (peaks(peakIndex) >= currentChunkIndex
              && peaks(peakIndex) < endOfChunk) {
          aux(endOfChunk, peakIndex + 1)
        }
        else {
          aux(currentChunkIndex, peakIndex + 1)
        }
      }
    }

    aux(0, 0)
  }


  def peaks(arr: Array[Int]): IndexedSeq[Int] = {
    (1 until arr.length - 1).filter ( i =>
        arr(i) > arr(i+1) && arr(i) > arr(i-1)
    )
  }