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 Position Find( List L, ElementType X ) { List l=L; for(; l!=NULL; l=l->Next) { if(l->Data==X) return l; } return ERROR; } List Insert( List L, ElementType X, Position P ) { if(L==NULL) { L=(List) malloc(sizeof(struct LNode)); L->Data=X; L->Next=NULL; return L; } /* if(P==NULL) { printf("Wrong Position for Insertion"); return ERROR; }*/ List t=(List) malloc(sizeof(struct LNode)),y=L; t->Data=X; if(L==P) { t->Next=L; return t; } while(y->Next!=P) { y=y->Next; if(y==NULL) { printf("Wrong Position for Insertion\n"); return ERROR; } } y->Next=t; t->Next=P; return L; } List Delete( List L, Position P ) { List t=L; if(t==P) { L=L->Next; return L; } while(t->Next!=P) { t=t->Next; if(t==NULL) { printf("Wrong Position for Deletion\n"); return ERROR; } } t->Next=P->Next; free(P); return L; } 文章来源: 链式表操作集