6-11 鏈式表操作集 （20 分）
本題要求實現鏈式表的操作集。
函數接口定義：
Position Find( List L, ElementType X );
List Insert( List L, ElementType X, Position P );
List Delete( List L, Position P );
其中List結構定義如下：
typedef struct LNode *PtrToLNode;
struct LNode {
ElementType Data;
PtrToLNode Next;
};
typedef PtrToLNode Position;
typedef PtrToLNode List;
各個操作函數的定義爲：
Position Find( List L, ElementType X )：返回線性表中首次出現X的位置。若找不到則返回ERROR；
List Insert( List L, ElementType X, Position P )：將X插入在位置P指向的結點之前，返回鏈表的表頭。如果參數P指向非法位置，則打印“Wrong Position for Insertion”，返回ERROR；
List Delete( List L, Position P )：將位置P的元素刪除並返回鏈表的表頭。若參數P指向非法位置，則打印“Wrong Position for Deletion”並返回ERROR。
裁判測試程序樣例：
#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;
}
/* 你的代碼將被嵌在這裏 */
輸入樣例：
6
12 2 4 87 10 2
4
2 12 87 5
輸出樣例：
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 ) {
List p=L;
while(p!=NULL){
if(p->Data ==X)
return p;
p=p->Next;
}
return ERROR;
}
List Insert(List L, ElementType X, Position P) {
List a = (List)malloc(sizeof(struct LNode));
a->Data = X;
List temp = L;
if (temp == P) {
a->Next = P;
return a;
}
while (temp != NULL) {
if (temp->Next == P) {
a->Next = P;
temp->Next = a;
return L;
}
temp = temp->Next;
}
printf("Wrong Position for Insertion\n");
return ERROR;
}
List Delete(List L, Position P) {
if (L == P) {
L = L->Next;
free(P);
return L;
}
List temp = L;
while (temp != NULL) {
if (temp->Next == P) {
temp->Next = P->Next;
free(P);
return L;
}
temp = temp->Next;
}
printf("Wrong Position for Deletion\n");
return ERROR;
}