Problem A: 两个有序链表序列的合并

Problem Description

已知两个非降序链表序列S1与S2，设计函数构造出S1与S2的并集新非降序链表S3。

Input Description

输入分两行，分别在每行给出由若干个正整数构成的非降序序列，用−1表示序列的结尾（−1不属于这个序列）。数字用空格间隔。

Output Description

在一行中输出合并后新的非降序链表，数字间用空格分开，结尾不能有多余空格；若新链表为空，输出NULL。

Sample Input

1 3 5 -1
2 4 6 8 10 -1

Sample Output

1 2 3 4 5 6 8 10

Hint

链表

我开始写的代码：

本来想写注释的但没有时间，期末在补吧······

#include 
using namespace std;
 
typedef struct LNode
{
	int date;
	struct LNode *next;
}LNode, *LinkList;
 
void InsterList(LinkList &S1)
{
	LinkList p;
	p = S1;
	int n;
	cin >> n;
	while (n != -1)
	{
		LinkList s = (LinkList)malloc(sizeof(LNode));
		s->date = n;
		s->next = NULL;
		p->next = s;
		p = p->next;
		cin >> n;
	}
}
 
void PrintList(LinkList S)
{
	LinkList p;
	p = S->next;
	if (p == NULL)
	{
		cout << "NULL" << endl;
	}
	else
	{
		int i = 0;
		while (p != NULL)
		{
			if (i++ > 0)
			{
				cout << " ";
			}
			cout << p->date;
 
			p = p->next;
		}
		cout << endl;
	}
}
 
void SortLink(LinkList &S1, LinkList &S2, LinkList &S3)
{
	LinkList pa, pb;
	LinkList pc;
	pa = S1->next;
	pb = S2->next;
	S3 = S1;
	pc = S3;
	while (pa && pb)
	{
		if (pa->date <= pb->date)
		{
			pc->next = pa;
			pc = pa;
			pa = pa->next;
		}
		else
		{
			pc->next = pb;
			pc = pb;
			pb = pb->next;
		}
	}
	pc->next = pa ? pa : pb;
	delete S2;
}
int main()
{
	LinkList S1 = (LinkList)malloc(sizeof(LNode));
	LinkList S2 = (LinkList)malloc(sizeof(LNode));
	LinkList S3 = (LinkList)malloc(sizeof(LNode));
	S1->next = NULL;
	S2->next = NULL;
	S3->next = NULL;
	int n;
	InsterList(S1);
	InsterList(S2);
	SortLink(S1, S2, S3);
	PrintList(S3);
	return 0;
}