PTA 数据结构与算法题目集（中文）6-5 链式表操作集

偏执的太偏执、 2022-05-24 13:22 218阅读 0赞

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

作者: 陈越

单位: 浙江大学

时间限制: 400ms

内存限制: 64MB

代码长度限制: 16KB

Position Find( List L, ElementType X ){
      while(L){
        if(L->Data == X){
          return L;
        }
        L = L->Next;
      }
      return ERROR;
    }
    
    List Insert( List L, ElementType X, Position P ){
      if(P == L){
        List Node = (List)malloc(sizeof(List));
        Node->Data = X;
        Node->Next = L;
        return Node;
      }
      List q = L;
      while(q){
        if(q->Next == P){
          List Node = (List)malloc(sizeof(List));
          Node->Data = X;
          Node->Next = q->Next;
          q->Next = Node;
          return L;
        }
        q = q->Next;
      }
      printf("Wrong Position for Insertion\n");
      return ERROR;
    }
    
    List Delete( List L, Position P ){
      if(L == P){
        return L->Next;
      }
      List q = L;
      while(q){
        if(q->Next == P){
          q->Next = q->Next->Next;
          return L;
        }
        q = q->Next;
      }
      printf("Wrong Position for Deletion\n");
      return ERROR;
    }