快速排序（i和j交互法）

/**
 * @author wxl
 * @Title: QuickSort
 * @ProjectName test
 * @Description: TODO
 * @date 2019-4-19 18:24
 */
public class QuickSort {
    public static void main(String[] args) {
        int[] a={10,9,7,3,3,8,6};

        for(int i=0;i<a.length;i++){
            System.out.print(a[i]+ " ");
        }
        System.out.println();

        sort(a,0,a.length-1);

        for(int i=0;i<a.length;i++){
            System.out.print(a[i]+ " ");
        }
        System.out.println();
    }

    public static void sort(int[] a,int l,int r){
        if(l<r){
            int x=a[l],i=l,j=r;
            while(i<j){
                while(i<j&&a[j]>=x){
                    j--;
                }
                while(i<j&&a[i]<=x){
                    i++;
                }
                if(i<j){
                    a[i]^=a[j];
                    a[j]^=a[i];
                    a[i]^=a[j];
                }
            }

            a[l]=a[i];
            a[i]=x;

            sort(a,l,i-1);
            sort(a,i+1,r);
        }
    }
}