02-线性结构1 两个有序链表序列的合并 (15分)

题目已知部分

#include 
#include 

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;
}

读入

List Read()
{
	ElementType n, data;
	scanf("%d", &n);
	
	List L, p,last;
	L = (List)malloc(sizeof(struct Node));             // 给头指针分配一个内存 
	last=L;
	
	int i;
	for (i=0; i<n; i++){
		scanf("%d", &data);
		p = (List)malloc(sizeof(struct Node));         // 给要加入的 p分配一个内存 
		p->Data = data;
		p->Next = NULL;
		last->Next = p;                               // 把 p接到链表 L上，并让最后一个（last）变为 p 
		last = p;
	}
	return L;
}

输出

void Print(List L)
{
	List p;
	p = L->Next; 
	if (p == NULL){
		printf("NULL\n");
		return;
	}
	for ( ; p != NULL; p=p->Next)
		printf("%d ", p->Data);
	printf("\n");
}

合并排序

List Merge (List L1, List L2)
{
	List L,p1,p2,last;
	p1=L1->Next;
	p2=L2->Next;
	
	L = (List)malloc(sizeof(struct Node));                   // 建一个新链表 
	last = L;
	
	while (p1 != NULL && p2!= NULL){
		if (p1->Data <= p2->Data){
			last->Next = p1;                                // 同上同上 
			last = p1;
			p1 = p1->Next;
		}
		else{
			last->Next = p2;
			last = p2;
			p2 = p2->Next;
		}
	}
	
	if (p1 != NULL)                                         // 把还有剩余的链表接到 L上 
		last->Next = p1;
	else
		last->Next = p2;
		
	L1->Next = NULL;                                       // L1 L2置空 
	L2->Next = NULL;
	
	return L;
}