链表归并

以前gx同学问的某某公司的笔试题，写一下练练（纯手写，没编译过），我也要找工作，准备一下笔试了：

typedef struct Node {
	int data;
	struct Node *next;
}Node;

Node * merge(Node *pa,Node *pb){
	Node *header;
	Node *p1;
	Node *p2;
	Node *p = pa;
	Node *q = pb;

	header = (Node *)malloc(sizeof(Node));
	header->next = NULL;
	Node *tail = header;
	
	while(p != NULL && q != NULL){
		p1 = p,p2 = q;
		if(p1->data < p2->data){
			tail->next = p1;
			p = p1->next;
			p1->next = NULL;				
		}else{
			tail->next = p2;
			q = p2->next;
			p2->next = NULL;
		}
		tail = tail->next;
	}

	if(p != NULL){
		tail->next = p;
	}

	if(q != NULL){
		tail->next = q;
	}
	return header;
}

 gx上次开始让我给写这个，结果他笔试的时候居然让写个递归的：

void merge(Node *tail,Node *pa,Node *pb){
   Node *p = NULL;
   if(pa != NULL && pb != NULL){
	if(pa->data < pb->data){
		tail->next = pa;
		p = pa->next;
		pa->next = NULL;
		merge(pa,p,pb);
	}else{
		tail->next = pb;
		p = pb->next;
		pb->next = NULL;
		merge(pb,pa,p);
	}
    }
   
   if(pa == NULL)
	tail->next = pb;
   if(pb == NULL)
	tail->next = pa;
}