Quicksort trên Danh sách liên kết đơn

void quick_sort(LIST &&l)  
{        
	LIST l1;LIST l2;  
	if(l.pHead==NULL) // rong  
		return;  
	else
	{		
		khoitao(l1);  
		khoitao(l2);  
		NODE *x=l.pHead;  
		l.pHead=x->pNext;  
		while(l.pHead!=NULL)
		{  
			NODE *p=l.pHead;  
			l.pHead=p->pNext;  
			p->pNext=NULL;  
			if(p->data<=x->data)  
				themdau2(l1,p);  
			else  
				themdau2(l2,p);  
		}  
		quick_sort(l1);  
		quick_sort(l2);  
		if(l1.pHead==NULL)  
			l.pHead=x;  
		else  
		{  
			l.pHead = l1.pHead;  
			l1.pTail->pNext = x;  
		}  
		x->pNext = l2.pHead;    
		if(l2.pHead==NULL)  
			l.pTail = x;  
		else  
		{  
			l.pTail = l2.pTail;  
		}  
	}
}