6-4 两个有序链表序列的合并PTA

Question

问题遇到的现象和发生背景

#####裁判代码:

#include <stdio.h>
#include <stdlib.h>

typedef int ElementType;
typedef struct Node *PtrToNode;
struct Node {
    ElementType Data;

| 表头 | 表头 |
| ------ | ------ |
| 单元格 | 单元格 |
| 单元格 | 单元格 |


    PtrToNode   Next;
};
typedef PtrToNode List;

List Read(); /* 细节在此不表 */
void Print( List L ); /* 细节在此不表；空链表将输出NULL */

List Merge( List L1, List L2 );

int main()
{
    List L1, L2, L;
    L1 = Read();
    L2 = Read();
    L = Merge(L1, L2);
    Print(L);
    Print(L1);
    Print(L2);
    return 0;
}

/* 你的代码将被嵌在这里 */

问题相关代码，请勿粘贴截图

List Merge( List L1, List L2 ){
    List p = (List) malloc(sizeof (List));
    List p1 = (List) malloc(sizeof (List));
    while(1) {
        if (L1 == NULL || L2 == NULL){
            for(;L2;L2=L2->Next)
            {
                p1->Data=L2->Data;
                p1=p1->Next;
            }
            break;
        }

        while (L1->Data) {
            p->Data = L1->Data;
            while (L2->Data) {
                if (p->Data <= L2->Data) {
                    p1->Data = p->Data;
                    L2 = L2->Next;
                }
                else break;
            }
            L1 = L1->Next;
            p = p->Next;
            p1 = p1->Next;
        }
    }
    return p1;
}

运行结果及报错内容

a.c: In function ‘Read’:
a.c:17:2: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result]
scanf("%d", &N);
^~~~~~~~~~~~~~~
a.c:22:3: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result]
scanf("%d", &Rear->Next->Data);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

我的解答思路和尝试过的方法

使用指针p,存放L1的内容.用p判断是否小于L2;如果小于则存放在指针p1.函数返回p1;

我想要达到的结果

Answer 1

if(scanf("%d", &N)){
}

if(scanf("%d", &Rear->Next->Data)){
}