scala数据结构和算法-01-用scala实现合并排序

package data

import scala.collection.mutable.ListBuffer
import scala.util.control.Breaks

object MergeSort {
  def mergeSort[T](compatator:(T,T)=>Boolean)(source:List[T]):List[T]={
    if(source.length==1){
      return source
    }
    if(source.length==0){
      return List()
    }
    val splited=source.splitAt(source.length/2);
    val leftSorted=mergeSort(compatator)(splited._1);
    val rightSorted=mergeSort(compatator)(splited._2);
    merge(compatator)(leftSorted,rightSorted);
  }
  
  def merge[T](compatator:(T,T)=>Boolean)(left:List[T],right:List[T]):List[T]={
    var indexLeft=0;
    var indexRight=0;
    var listBuffer=ListBuffer[T]();
    Breaks.breakable{
      while(true){
        if(compatator(left(indexLeft),right(indexRight))){
          listBuffer+=left(indexLeft)
          indexLeft+=1;
        }else{
          listBuffer+=right(indexRight)
          indexRight+=1
        }
        if(indexLeft==left.length){
          listBuffer.appendAll(right.slice(indexRight,right.length))
          Breaks.break;
        }
        if(indexRight==right.length){
          listBuffer.appendAll(left.slice(indexLeft,left.length))
          Breaks.break;
        }
      }
    }
    listBuffer.toList
  }
  
  def main(args: Array[String]): Unit = {
    val source=List(1,3,9,8,4,7,5,6)
    println(mergeSort[Int]((x,y)=>{ if (x<y)  true else  false})(source))
  }
}