基本思想是：通过一趟排序将待排序记录分成独立的两部分，其中一部分的关键字均比另一部分的关键字小，再分别对这两部分进行排序。

（1）将数组分成左右两部分

（2）递归调用自身对左右两部分排序

 public void recQuickSort(int left,int right){int partition = partitionIt(left,right);recQuickSort(left,partition-1);recQuickSort(partition+1,right);}

 package Structure;class ArrayIns{private long[] theArray;private int nElems;public ArrayIns(int max){theArray = new long[max];nElems = 0;}public void insert(long value){theArray[nElems] = value;nElems++;}public void display(){System.out.print("A=");for(int j=0;j<nElems;j++){System.out.print(theArray[j] + " ");//System.out.println("");}}public void quickSort(){recQuickSort(0,nElems-1);}public void recQuickSort(int left,int right){int size = right-left+1;if(size<=3)manualSort(left,right);else{long medium = medianOf3(left,right);int partition = partitionIt(left,right,medium);recQuickSort(left,partition-1);recQuickSort(partition+1,right);}}//三个数据项取中public long medianOf3(int left,int right){int center = (left+right)/2;if(theArray[left]>theArray[center])swap(left,center);if(theArray[left]>theArray[right])swap(left,right);if(theArray[center]>theArray[right])swap(center,right);swap(center,right-1);return theArray[right-1];}public void swap(int dex1,int dex2){long temp = theArray[dex2];theArray[dex2] = theArray[dex1];theArray[dex1] = temp;}public int partitionIt(int left,int right,long pivot){int leftPtr = left;int rightPtr = right - 1;while(true){while(theArray[++leftPtr]<pivot);while(theArray[--rightPtr]>pivot);if(leftPtr>=rightPtr)break;elseswap(leftPtr,rightPtr);}swap(leftPtr,right-1);return leftPtr;}//对只有三个或更少数数据项数组进行排序public void manualSort(int left,int right){int size = right - left + 1;if(size<=1)return;if(size==2){if(theArray[left]>theArray[right])swap(left,right);return;}else{if(theArray[left]>theArray[right-1])swap(left,right-1);if(theArray[left]>theArray[right])swap(left,right);if(theArray[right-1]>theArray[right])swap(right-1,right);}}
}
public class QuickSort3 {public static void main(String[] args){int maxSize = 16;ArrayIns arr;arr = new ArrayIns(maxSize);for(int j=0;j<maxSize;j++){long n = (int)(java.lang.Math.random()*99);arr.insert(n);}arr.display();arr.quickSort();arr.display();}
}