快排

package com.algorithm;


public class QuickSort {
	public static void main(String []args){
		int []a={4,4,5,7,1,8,3,9,11,6};
		quickSort(a,0,a.length-1);
		for(int i=0;i<a.length;i++)
			System.out.println(a[i]);
	}
	private static void quickSort(int[] a, int i, int j) {
		// TODO 自动生成的方法存根
		int mid=0;
		if(i<j){
			//递归地找分割点，排左边，排右边 
			mid=findP(a,i,j);
			quickSort(a,i,mid-1);
			quickSort(a,mid+1,j);
		}
	}
	private static int findP(int[] a, int i, int j){
		int m=a[i];
		while(i<j){
			while(i<j&&a[j]>m)j--;
			a[i]=a[j];


			while(i<j&&a[i]<=m)i++;
			a[j]=a[i];
		}
		a[i]=m;
		return i;
	}
 static int partition(int[] ar,int i,int l) {
      int res=0,temp=ar[i];
         List<Integer> list=new LinkedList<>();
         for(int k=i;k<=l;k++)
             list.add(ar[k]);
         
         for(int k=i+1;k<=l;k++){
             if(ar[k]<temp){
              list.remove((Integer)ar[k]);
                 list.add(res,ar[k]);
                 res++;
             }
         }
         for(int k=i;k<=l;k++)
             ar[k]=list.get(k-i);
         return res+i;
     }}
//为了得到相对顺序不变的序列，eg：5 8 1 3 7 9 2->1 3 2 5 8 7 9