7-15 两个有序链表序列的合并（20 分）

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。

输入格式:

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。

输出格式:

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。

输入样例:

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

输出样例:

1 2 3 4 5 6 8 10


代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct Node *Node;
struct Node
{
    int data;
    Node Next;
};
Node CList()
{
    int d;
    Node head = (Node)malloc(sizeof(struct Node)),q;
    head -> Next = NULL;
    q = head;
    while(~scanf("%d",&d)&&d!=-1)
    {
        Node p = (Node)malloc(sizeof(struct Node));
        p -> data = d;
        p -> Next = NULL;
        q -> Next = p;
        q = p;
    }
    return head;
}
Node Merge(Node a,Node b)
{
    a = a -> Next;
    b = b -> Next;
    Node head = (Node)malloc(sizeof(struct Node));
    head -> Next = NULL;
    Node q = head;
    while(a || b)
    {
        Node p = (Node)malloc(sizeof(struct Node));
        p -> Next = NULL;
        if(a == NULL || a -> data > b -> data)
        {
            p -> data = b -> data;
            b = b -> Next;
            q -> Next = p;
            q = p;
        }
        else
        {
            p -> data = a -> data;
            a = a -> Next;
            q -> Next = p;
            q = p;
        }
    }
    return head;
}
void printL(Node a)
{
    a = a -> Next;
    if(a == NULL)printf("NULL");
    int flag = 0;
    while(a)
    {
        if(flag)printf(" %d",a -> data);
        else printf("%d",a -> data);
        a = a -> Next;
        flag = 1;
    }
}
int main()
{
    Node a = CList();
    Node b = CList();
    Node c = Merge(a,b);
    printL(c);
}