为什么我在Scala中的二进制搜索实现如此缓慢?

最近,我实现了这个二进制搜索,Scala应该在6秒内运行,但它在检查分配的机器上运行12-13秒。

阅读代码前请注意:输入由两行组成:第一行是要搜索的数字列表,第二行是要在数字列表中搜索的“搜索词”列表。预期输出只列出数字列表中每个术语的索引。每个输入的最大长度为10^5,每个数字的最大大小为10^9。

例如:

Input:
5 1 5 8 12 13 //note, that the first number 5 indicates the length of the 
following sequence

5 8 1 23 1 11 //note, that the first number 5 indicates the length of the 
following sequence

Output:
2 0 -1 0 -1 // index of each term in the input array

我的解决方案:

object BinarySearch extends App {
  val n_items = readLine().split(" ").map(BigInt(_))
  val n = n_items(0)
  val items = n_items.drop(1)

  val k :: terms = readLine().split(" ").map(BigInt(_)).toList

  println(search(terms, items).mkString(" "))

  def search(terms: List[BigInt], items:Array[BigInt]): Array[BigInt] = {
    @tailrec
    def go(terms: List[BigInt], results: Array[BigInt]): Array[BigInt] = terms match {
      case List() => results
      case head :: tail => go(tail, results :+ find(head))
    }

    def find(term: BigInt): BigInt = {
      @tailrec
      def go(left: BigInt, right: BigInt): BigInt = {
        if (left > right) { -1 }
        else {
          val middle = left + (right - left) / 2
          val middle_val = items(middle.toInt)

          middle_val match {
            case m if m == term => middle
            case m if m <= term => go(middle + 1, right)
            case m if m > term => go(left, middle - 1)
          }
        }
      }

      go(0, n - 1)
    }

    go(terms, Array())
  }
}

这段代码为什么这么慢?非常感谢。