scala数据结构和算法-04-快速排序实现

package data

import scala.collection.mutable.ListBuffer
import scala.collection.mutable.ListBuffer

object QuickSort {
  
  def quickSort[T<% Ordered[T]](source:ListBuffer[T],left:Int,right:Int):ListBuffer[T]={
    if(left==right)ListBuffer()
    else{
      val index=partition(source,left,right)
      if(left==index){
         if(right-index>=2){
           quickSort(source,index+1,right)
         }
      }else if(right==index){
        if(index-left>=2){
          quickSort(source,left,index-1)
        }
      }else{
        if(index-left>=2){
          quickSort(source,left,index-1)
        }
        if(right-index>=2){
          quickSort(source,index+1,right)
        }
      }
     
      source
    }
  }
  
  def partition[T<%Ordered[T]](source:ListBuffer[T],left:Int,right:Int):Int={
      val cmp=source(left)
      var leftIndex=left
      var rightIndex=right
      var direction=true;
      while(leftIndex<rightIndex){
        if(direction){
          if(source(rightIndex)<cmp){ 
            source(leftIndex)=source(rightIndex);
            leftIndex+=1;
            direction=(!direction);
          }else{
            if(leftIndex<rightIndex){
              rightIndex-=1;
            }
          }
        }
        if(!direction){
          if(source(leftIndex)>=cmp){
            source(rightIndex)=source(leftIndex)
            rightIndex-=1
            direction=(!direction);
          }else{
            if(leftIndex<rightIndex){
              leftIndex+=1;
            }
          }
        }
        
      }
      source(leftIndex)=cmp;
      leftIndex
  }
  
  
  def main(args: Array[String]): Unit = {
    val source=ListBuffer(1,3,7,5,4,15,3,9,6,8,33,12,14,12,17,16,18);
     println(quickSort(source,0,source.length-1).mkString(","))
  }
}