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
");
}
scanf("%d", &N);
while ( N-- ) {
scanf("%d", &X);
P = Find(L, X);
if ( P == ERROR )
printf("Finding Error: %d is not in.
", X);
else {
flag = Delete(L, P);
printf("%d is found and deleted.
", X);
if ( flag==false )
printf("Wrong Answer.
");
}
}
flag = Insert(L, X, NULL);
if ( flag==false ) printf("Wrong Answer
");
else
printf("%d is inserted as the last element.
", X);
P = (Position)malloc(sizeof(struct LNode));
flag = Insert(L, X, P);
if ( flag==true ) printf("Wrong Answer
");
flag = Delete(L, P);
if ( flag==true ) printf("Wrong Answer
");
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 List MakeEmpty()
{
List L = (List)malloc(sizeof(struct LNode));
L->Next = NULL;
return L;
}
Position Find(List L, ElementType X)
{
L = L->Next;
while (L)
{
if (L->Data == X)
return L;
if (L->Data != X)
L = L->Next;
}
return ERROR;
}
bool Insert(List L, ElementType X, Position P)
{
List temp = (List)malloc(sizeof(struct LNode));
temp->Next = NULL;
temp->Data = X;
//与6-5的区别就是在这里，不用讨论插入是头节点的情况
while (L->Next)
{
if (P == L->Next)
{
temp->Next = L->Next;
L->Next = temp;
return true;
}
L = L->Next;
}
if (P == NULL)
{
L->Next = temp;
return true;
}
else
{
printf("Wrong Position for Insertion ");
return false;
}
}
bool Delete(List L, Position P)
{
List temp, pre;
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 true;
}
if (L->Next == P&&L->Next->Next == NULL)
{
temp = L->Next;
L->Next = NULL;
free(temp);
return true;
}
pre = pre->Next;
L = L->Next;
}
printf("Wrong Position for Deletion ");
return false;
}