快速排序的Java实现

public class QuickSort{
public static int[] quick_sort(int a[], int len) {
if(len == 1 || len == 0) return a;
Random random = new Random();
int k = random.nextInt(len);

int al[] = new int[len];
int ar[] = new int[len];
int len1 = 0, len2 = 0;
for(int i = 0; i < len; ++i) {
if(a[i] <= a[k]) al[len1++] = a[i];
else ar[len2++] = a[i];
}
al = quick_sort(al, len1);
ar = quick_sort(ar, len2);
for(int i = 0; i < len1; ++i) a[i] = al[i];
for(int i = 0; i < len2; ++i) a[len1++] = ar[i];
return a;
}

public static void main(String[] args) {
int a[] = {10, 9, 3, 4, 6, 7, 1};
a = QuickSort.quick_sort(a, a.length);
for(int i = 0; i < a.length; ++i) {
System.out.print(a[i] + " ");
}
}
}
/*Output
1 3 4 6 7 9 10
*/