算法(第四版)快速排序

写快排的时候遇到了不少困难，虽然只有几行代码
得到的最重要的体会是左侧的指针（i）最终会在右侧的指针（j）的右边，也就是最终停止的时候j+1 = i(永远只会停到这里)
参考了文章http://blog.csdn.net/kwang0131/article/details/51085734
解释的很清晰

package suanfa;

import com.algs4.stdlib.StdOut;

/**
 * Created by evan on 16/11/24.
 * 二分快速排序
 */

public class quickSort {

    public static void main(String[] args){

        Integer[] papapa = {4,9,6,5,11,13,22,66};
        sort(papapa,0,papapa.length-1);

        for (Integer value:papapa) {

            StdOut.println(value);
        }
    }

    public static void sort(Comparable[] intList,int low, int high){

        if(low>=high){
            return;
        }

        int mid = partition(intList,low,high);


        sort(intList,low,mid-1);
        sort(intList,mid+1,high);

    }

    public static Boolean less(Comparable a, Comparable b){

        return a.compareTo(b) < 0;

    }


    public static int partition(Comparable[] a,int lo,int hi){


        int i = lo;
        int j = hi+1;
        Comparable v = a[lo];
        while (true){

            while(less(a[++i],v)){}
            while(less(v,a[--j])){}

            if (i >= j){
                break;
            }

            exch(a,i,j);
        }
        
        exch(a,j,lo);
        return j;
    }

    public static void exch(Comparable[] intList,int low,int high){
        Comparable tmp = intList[low];
        intList[low] = intList[high];
        intList[high] = tmp;
    }

}