PTA两个有序链表序列的合并

本题要求实现一个函数，将两个链表表示的递增整数序列合并为一个非递减的整数序列。

函数接口定义：

 

List Merge( List L1, List L2 );

 

其中List结构定义如下：

 

typedef struct Node *PtrToNode;
struct Node {
    ElementType Data; /* 存储结点数据 */
    PtrToNode   Next; /* 指向下一个结点的指针 */
};
typedef PtrToNode List; /* 定义单链表类型 */

 

L1和L2是给定的带头结点的单链表，其结点存储的数据是递增有序的；函数Merge要将L1和L2合并为一个非递减的整数序列。应直接使用原序列中的结点，返回归并后的带头结点的链表头指针。

裁判测试程序样例：

 

#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 */

 

输入样例：

3
1 3 5
5
2 4 6 8 10

 

输出样例：

1 2 3 4 5 6 8 10 
NULL
NULL

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

typedef int ElementType;
typedef struct Node *PtrToNode;
struct Node {
    ElementType Data;
    PtrToNode   Next;
};
typedef PtrToNode List;

List Read(void); /* 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 Read(void){
    List L = (List)malloc(sizeof(struct Node));
    List p,rear,t;
    rear = L;
    L->Next = NULL;
    int n,data;
    scanf("%d",&n);
    while (n--) {
        scanf("%d",&data);
        p = (PtrToNode)malloc(sizeof(struct Node));
        p->Data = data;
        p->Next = NULL;
        rear->Next = p;
        rear = p;
    }
    return L;
}

void Print( List L ){
    List p = L->Next;
    int flag = 0;
    if(p == NULL){
        printf("NULL\n");
        return;
    }
    while (p) {
        if(!flag){
            flag = 1;
            printf("%d",p->Data);
        }else{
            printf(" %d",p->Data);
        }
        p = p->Next;
    }
    printf("\n");
}

List Merge( List L1, List L2 ){
    List p = (List)malloc(sizeof(struct Node));
    List rear = p;
    List t;
    p->Next = NULL;
    List t1 = L1->Next, t2 = L2->Next;
    while (t1 && t2) {
        t = (List)malloc(sizeof(struct Node));
        t->Next = NULL;
        if(t1->Data <= t2->Data){
            t->Data = t1->Data;
            rear->Next = t;
            rear = t;
            t = t1;
            t1 = t1->Next;
            free(t);
  //          printf("%d\n",rear->Data);
        }else{
            t->Data = t2->Data;
            rear->Next = t;
            rear = t;
            t = t2;
            t2 = t2->Next;
            free(t);
//            printf("%d\n",rear->Data);
        }
    }
    while (t1) {
        t = (List)malloc(sizeof(struct Node));
        t->Next = NULL;
        t->Data = t1->Data;
        rear->Next = t;
        rear = t;
        t = t1;
        t1 = t1->Next;
        free(t);
  //      printf("%d\n",rear->Data);
    }
    while (t2) {
        t = (List)malloc(sizeof(struct Node));
        t->Next = NULL;
        t->Data = t2->Data;
        rear->Next = t;
        rear = t;
        t = t2;
        t2 = t2->Next;
        free(t);
 //       printf("%d\n",rear->Data);
    }
    L1->Next = NULL;
    L2->Next = NULL;
    return p;
}