PTA 数据结构与算法题目集（中文）6-6 带头结点的链式表操作集

客官°小女子只卖身不卖艺 2022-05-23 04:49 251阅读 0赞

#### 6-6 带头结点的链式表操作集（20 分） ####

本题要求实现带头结点的链式表操作集。

### 函数接口定义： ###

List MakeEmpty(); 
    Position Find( List L, ElementType X );
    bool Insert( List L, ElementType X, Position P );
    bool 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：

`List MakeEmpty()`：创建并返回一个空的线性表；

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

`bool Insert( List L, ElementType X, Position P )`：将X插入在位置P指向的结点之前，返回true。如果参数P指向非法位置，则打印“Wrong Position for Insertion”，返回false；

`bool Delete( List L, Position P )`：将位置P的元素删除并返回true。若参数P指向非法位置，则打印“Wrong Position for Deletion”并返回false。

### 裁判测试程序样例： ###

#include <stdio.h>
    #include <stdlib.h>
    
    #define ERROR NULL
    typedef enum {false, true} bool;
    typedef int ElementType;
    typedef struct LNode *PtrToLNode;
    struct LNode {
        ElementType Data;
        PtrToLNode Next;
    };
    typedef PtrToLNode Position;
    typedef PtrToLNode List;
    
    List MakeEmpty(); 
    Position Find( List L, ElementType X );
    bool Insert( List L, ElementType X, Position P );
    bool Delete( List L, Position P );
    
    int main()
    {
        List L;
        ElementType X;
        Position P;
        int N;
        bool flag;
    
        L = MakeEmpty();
        scanf("%d", &N);
        while ( N-- ) {
            scanf("%d", &X);
            flag = Insert(L, X, L->Next);
            if ( flag==false ) 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 {
                flag = Delete(L, P);
                printf("%d is found and deleted.\n", X);
                if ( flag==false )
                    printf("Wrong Answer.\n");
            }
        }
        flag = Insert(L, X, NULL);
        if ( flag==false ) printf("Wrong Answer\n");
        else
            printf("%d is inserted as the last element.\n", X);
        P = (Position)malloc(sizeof(struct LNode));
        flag = Insert(L, X, P);
        if ( flag==true ) printf("Wrong Answer\n");
        flag = Delete(L, P);
        if ( flag==true ) printf("Wrong Answer\n");
        for ( P=L->Next; 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

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