【PTA】6-5 链式表操作集 (20分)
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：
1 #include <stdio.h> 2 #include <stdlib.h> 3 4 #define ERROR NULL 5 typedef int ElementType; 6 typedef struct LNode *PtrToLNode; 7 struct LNode { 8 ElementType Data; 9 PtrToLNode Next; 10 }; 11 typedef PtrToLNode Position; 12 typedef PtrToLNode List; 13 14 Position Find( List L, ElementType X ); 15 List Insert( List L, ElementType X, Position P ); 16 List Delete( List L, Position P ); 17 18 int main() 19 { 20 List L; 21 ElementType X; 22 Position P, tmp; 23 int N; 24 25 L = NULL; 26 scanf("%d", &N); 27 while ( N-- ) { 28 scanf("%d", &X); 29 L = Insert(L, X, L); 30 if ( L==ERROR ) printf("Wrong Answer "); 31 } 32 scanf("%d", &N); 33 while ( N-- ) { 34 scanf("%d", &X); 35 P = Find(L, X); 36 if ( P == ERROR ) 37 printf("Finding Error: %d is not in. ", X); 38 else { 39 L = Delete(L, P); 40 printf("%d is found and deleted. ", X); 41 if ( L==ERROR ) 42 printf("Wrong Answer or Empty List. "); 43 } 44 } 45 L = Insert(L, X, NULL); 46 if ( L==ERROR ) printf("Wrong Answer "); 47 else 48 printf("%d is inserted as the last element. ", X); 49 P = (Position)malloc(sizeof(struct LNode)); 50 tmp = Insert(L, X, P); 51 if ( tmp!=ERROR ) printf("Wrong Answer "); 52 tmp = Delete(L, P); 53 if ( tmp!=ERROR ) printf("Wrong Answer "); 54 for ( P=L; P; P = P->Next ) printf("%d ", P->Data); 55 return 0; 56 } 57 58 /* 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 函数实现细节：
1 Position Find( List L, ElementType X ){ 2 //if(L==NULL)return NULL; 3 while(L&&L->Data!=X){ 4 L=L->Next; 5 } 6 if(L==NULL){ 7 return NULL; 8 }else if(L->Data==X){ 9 return L; 10 } 11 } 12 13 List Insert( List L, ElementType X, Position P ){ 14 Position temp=(Position)malloc(sizeof(struct LNode)); 15 if(L==P){ 16 temp->Data=X;temp->Next=P; 17 return temp; 18 } 19 List Q=L; 20 while(L->Next&&L->Next!=P)L=L->Next; 21 if(P==NULL){ 22 temp->Data=X;temp->Next=NULL; 23 L->Next=temp; 24 return Q; 25 26 }else if(P &&L->Next==NULL){ 27 printf("Wrong Position for Insertion "); 28 return NULL; 29 } 30 temp->Data=X;temp->Next=P; 31 L->Next=temp; 32 return Q; 33 } 34 List Delete( List L, Position P ){ 35 Position Q=L; 36 if (L == P) { 37 L = L->Next; 38 free(P); 39 return L; 40 } 41 while (Q->Next != P && Q->Next != NULL)Q = Q->Next; 42 if(Q->Next==NULL){ 43 printf("Wrong Position for Deletion "); 44 return ERROR; 45 }else{ 46 Q->Next=P->Next; 47 free(P); 48 return L; 49 } 50 }