Scala冒泡排序、快排、归并

感谢heybiiiiii同学

http://blog.csdn.net/qq1010885678/article/details/46755749

1、冒泡排序

def sort(list: List[Int]): List[Int] = list match {
    case List() => List()
    case head :: tail => compute(head, sort(tail))
  }

  def compute(data: Int, dataSet: List[Int]): List[Int] = dataSet match {
    case List() => List(data)
    case head :: tail => if (data <= head) data :: dataSet else head :: compute(data, tail)
  }

def main(args: Array[String]) {
    val list = List(3, 12, 43, 23, 7, 1, 2, 0)
    println(sort(list))
  }

2、归并排序

def mergedSort[T](less: (T, T) => Boolean)(list: List[T]): List[T] = {

    def merged(xList: List[T], yList: List[T]): List[T] = {
      (xList, yList) match {
        case (Nil, _) => yList
        case (_, Nil) => xList
        case (x :: xTail, y :: yTail) => {
          if (less(x, y)) x :: merged(xTail, yList)
          else
            y :: merged(xList, yTail)
        }
      }
    }

    val n = list.length / 2
    if (n == 0) list
    else {
      val (x, y) = list splitAt n
      merged(mergedSort(less)(x), mergedSort(less)(y))
    }
  }

def main(args: Array[String]) {
    val list = List(3, 12, 43, 23, 7, 1, 2, 0)
    println(mergedSort((x: Int, y: Int) => x < y)(list))
  }

3、快速排序

  def quickSort(list: List[Int]): List[Int] = {
    list match {
      case Nil => Nil
      case List() => List()
      case head :: tail =>
        val (left, right) = tail.partition(_ < head)
        quickSort(left) ::: head :: quickSort(right)
    }
  }

def main(args: Array[String]) {
    val list = List(3, 12, 43, 23, 7, 1, 2, 0)
    println(quickSort(list))
  }