//
// functions to use insertion sort to sort list of integers,
// array of integers
//

// lists are immutable so we return the sorted result

def insertL(l : List[Int], elem : Int) : List[Int] = {
  if (l.isEmpty) {
    List(elem)
  }
  else if (elem < l.head) {
    elem :: l
  }
  else {
    l.head :: insertL(l.tail, elem)
  }
}

def insertionSortL(l : List[Int]) : List[Int] = {
  var out = List[Int]()
  for (elem <- l) {
    out = insertL(out, elem)
  }
  out
}

// arrays are mutable so we can sort in place

def insertA(a : Array[Int], indexToInsert : Int) {
    // insert element a(indexToInsert) into part of array to the left
    // doing repeated exchanges here is simple but maybe not efficient
    var index = indexToInsert
    while ((index > 0) && (a(index-1) > a(index))) {
      val temp = a(index-1)
      a(index-1) = a(index)
      a(index) = temp
      index -= 1
    }
}

def insertionSortA(a : Array[Int]) {
  for (i <- 1 until a.length) {
    insertA(a, i)
  }
}