7-15 兩個有序鏈表序列的合並（20 分）

已知兩個非降序鏈表序列S1與S2，設計函數構造出S1與S2的並集新非降序鏈表S3。

輸入格式:

輸入分兩行，分別在每行給出由若干個正整數構成的非降序序列，用−1表示序列的結尾（−1不屬於這個序列）。數字用空格間隔。

輸出格式:

在一行中輸出合並后新的非降序鏈表，數字間用空格分開，結尾不能有多余空格；若新鏈表為空，輸出NULL。

輸入樣例:

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

輸出樣例:

1 2 3 4 5 6 8 10


代碼：

#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);
}