PAT中国大学MOOC-陈越、何钦铭-数据结构-2020夏 函数题 ：02-线性结构1 两个有序链表序列的合并

题目：https://pintia.cn/problem-sets/1268384564738605056/problems/1271415149946912768

题解：https://blog.csdn.net/wanmeiwushang/article/details/52585327

题解代码：

List Merge(List L1, List L2) {        
    List L = (List)malloc(sizeof(struct Node));
    L->Next = NULL;
    List r = L;
    List p = L1->Next;
    List q = L2->Next;
    while (p!=NULL && q!=NULL) {
        if (p->Data < q->Data) {
            r->Next = p;
            p = p->Next;
            r = r->Next;
        }
        else {
            r->Next = q;
            q = q->Next;
            r = r->Next;
        }
    }
    if (p != NULL) r->Next = p;
    if (q != NULL) r->Next = q;
    L1->Next = NULL;
    L2->Next = NULL;

    return L;
}

 完整代码：

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

typedef int ElementType;
typedef struct Node* PtrToNode;
struct Node {
    ElementType Data;
    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 */
List Merge(List L1, List L2) {        
    List L = (List)malloc(sizeof(struct Node));
    L->Next = NULL;
    List r = L;
    List p = L1->Next;
    List q = L2->Next;
    while (p!=NULL && q!=NULL) {
        if (p->Data < q->Data) {
            r->Next = p;
            p = p->Next;
            r = r->Next;
        }
        else {
            r->Next = q;
            q = q->Next;
            r = r->Next;
        }
    }
    if (p != NULL) r->Next = p;
    if (q != NULL) r->Next = q;
    L1->Next = NULL;
    L2->Next = NULL;

    return L;
}
List Read()
{
    int len = 0;
    int num = 0;
    PtrToNode h = NULL;
    PtrToNode last = NULL;

    scanf("%d", &len);
    if (len == 0)
        return NULL;

    h = (PtrToNode)malloc(sizeof(struct Node));//建立头结点
    h->Next = NULL;
    last = h;
    while (len) {
        scanf("%d", &num);
        PtrToNode node = (PtrToNode)malloc(sizeof(struct Node));
        node->Data = num;
        node->Next = NULL;
        last->Next = node;
        last = node;
        len--;
    }
    return h;
}
void Print(List L)
{
    if (L->Next == NULL) {
        printf("NULL\n");
        return;
    }
    L = L->Next;
    while (L != NULL) {
        printf("%d ", L->Data);
        L = L->Next;
    }
    putchar('\n');
}