java快速排序

public class QuickSort {
   public void quick(int [] a){
      if(a.length>0){
         quickSort(a,0,a.length-1);
      }
   }
   /**
    * 快速排序
    * @param a
    */
   private void quickSort(int[] a, int low, int high) {
      if(low<high){
         int middle = getMiddle(a,low,high);
         quickSort(a, 0, middle-1);
         quickSort(a,middle+1,high);
      }
   }

   /**
    * 获取中间下标
    * @param a
    * @param low
    * @param high
    * @return
    */
   private int getMiddle(int[] a, int low, int high) {
      int temp = a[low];//基准元素
      while(low<high){
         while(low<high&&a[high]>=temp){
            high--;
         }
         a[low] = a[high];
         while(low<high&&a[low]<=temp){
            low++;
         }
         a[high] = a[low];
      }
      a[low] = temp;//插入到排序后正确的位置
      return low;
   }

   public static void main(String[] args){
      QuickSort quickSort = new QuickSort();
//    int [] a = {19,2,3,90,67,33,-7,24,3,56,34,5};
      int [] a = {19,10};
      quickSort.quick(a);
      for(int num :a){
         System.out.println(" "+num);
      }
   }