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;  
                    }  
    }