数据结构与算法题目集(中文)6-5 链式表操作集 (20分)

本题要求实现链式表的操作集。

函数接口定义:

Position Find( List L, ElementType X );
List Insert( List L, ElementType X, Position P );
List Delete( List L, Position P );

其中List结构定义如下:

typedef struct LNode *PtrToLNode;
struct LNode {
    ElementType Data;
    PtrToLNode Next;
};
typedef PtrToLNode Position;
typedef PtrToLNode List;

各个操作函数的定义为:

Position Find( List L, ElementType X ):返回线性表中首次出现X的位置。若找不到则返回ERROR;

List Insert( List L, ElementType X, Position P ):将X插入在位置P指向的结点之前,返回链表的表头。如果参数P指向非法位置,则打印“Wrong Position for Insertion”,返回ERROR;

List Delete( List L, Position P ):将位置P的元素删除并返回链表的表头。若参数P指向非法位置,则打印“Wrong Position for Deletion”并返回ERROR。

裁判测试程序样例:

#include 
#include 

#define ERROR NULL
typedef int ElementType;
typedef struct LNode *PtrToLNode;
struct LNode {
    ElementType Data;
    PtrToLNode Next;
};
typedef PtrToLNode Position;
typedef PtrToLNode List;

Position Find( List L, ElementType X );
List Insert( List L, ElementType X, Position P );
List Delete( List L, Position P );

int main()
{
    List L;
    ElementType X;
    Position P, tmp;
    int N;

    L = NULL;
    scanf("%d", &N);
    while ( N-- ) {
        scanf("%d", &X);
        L = Insert(L, X, L);
        if ( L==ERROR ) printf("Wrong Answer\n");
    }
    scanf("%d", &N);
    while ( N-- ) {
        scanf("%d", &X);
        P = Find(L, X);
        if ( P == ERROR )
            printf("Finding Error: %d is not in.\n", X);
        else {
            L = Delete(L, P);
            printf("%d is found and deleted.\n", X);
            if ( L==ERROR )
                printf("Wrong Answer or Empty List.\n");
        }
    }
    L = Insert(L, X, NULL);
    if ( L==ERROR ) printf("Wrong Answer\n");
    else
        printf("%d is inserted as the last element.\n", X);
    P = (Position)malloc(sizeof(struct LNode));
    tmp = Insert(L, X, P);
    if ( tmp!=ERROR ) printf("Wrong Answer\n");
    tmp = Delete(L, P);
    if ( tmp!=ERROR ) printf("Wrong Answer\n");
    for ( P=L; P; P = P->Next ) printf("%d ", P->Data);
    return 0;
}

/* 你的代码将被嵌在这里 */

输入样例:

6
12 2 4 87 10 2
4
2 12 87 5

输出样例:

2 is found and deleted.
12 is found and deleted.
87 is found and deleted.
Finding Error: 5 is not in.
5 is inserted as the last element.
Wrong Position for Insertion
Wrong Position for Deletion
10 4 2 5 

 

Position Find(List L, ElementType X)

{

    while (L)

    {

        if (L->Data == X)

            return L;

        if (L->Data != X)

            L = L->Next;

 

    }

    return ERROR;

}在顺序表中是一次性申请好所有的空间,在插入的时候无需重新申请空间,而在链式表中每插入一次数据都要申请一次空间

//注意:

List Insert(List L, ElementType X, Position P)

{

    List temp = (List)malloc(sizeof(struct LNode));//注意申请空间的格式写法

    temp->Next = NULL;

    temp->Data = X;

    List head = L;//无论L链表如何改变,最终返回的都是链表的表头,所以使用head记录链表的表头

    if (P == L)//如果是在头结点插入的话要另外处理

    {

        temp->Next = L;

        return temp;

    }

    while (L->Next)

    {

        if (P == L->Next)

        {

            temp->Next = L->Next;//注意插入的顺序

            L->Next = temp;

            return head;

        }

        L = L->Next;

    }

    if (P == NULL)//指向链表中的最后一个

    {

        L->Next = temp;

        return head;

    }

    else

    {

        printf("Wrong Position for Insertion\n");

        return ERROR;

    }

}

List Delete(List L, Position P)

{

    List temp,pre,head;

    if (P == L)//删除节点在开头的情况

    {

        temp = L;

        L = L->Next;

        free(temp);

        return L;

    }

    head = L;

    if (L->Next)

        pre = L->Next;

    while (L->Next)

    {

        if (L->Next == P&&L->Next->Next != NULL)

        {

            temp = L->Next;

            pre = L->Next->Next;

            L->Next = pre;

            free(temp);

            return head;

        }

        if (L->Next == P&&L->Next->Next == NULL)//特别讨论一下删除最后一个节点的情况

        {

            temp = L->Next;

            L->Next = NULL;

            free(temp);

            return head;

        }

        pre = pre->Next;

        L = L->Next;

    }

    printf("Wrong Position for Deletion\n");

    return ERROR;

}

 

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