本题要求实现两个函数,分别将读入的数据存储为单链表、将链表中偶数值的结点删除。链表结点定义如下:
struct ListNode {
int data;
struct ListNode *next;
};
函数接口定义:
struct ListNode *createlist();
struct ListNode *deleteeven( struct ListNode *head );
函数createlist从标准输入读入一系列正整数,按照读入顺序建立单链表。当读到−1时表示输入结束,函数应返回指向单链表头结点的指针。
函数deleteeven将单链表head中偶数值的结点删除,返回结果链表的头指针。
裁判测试程序样例:
#include <stdio.h>
#include <stdlib.h>
struct ListNode {
int data;
struct ListNode *next;
};
struct ListNode *createlist();
struct ListNode *deleteeven( struct ListNode *head );
void printlist( struct ListNode *head )
{
struct ListNode *p = head;
while (p) {
printf("%d ", p->data);
p = p->next;
}
printf("\n");
}
int main()
{
struct ListNode *head;
head = createlist();
head = deleteeven(head);
printlist(head);
return 0;
}
/* 你的代码将被嵌在这里 */
struct ListNode *createlist(){
struct ListNode *head=NULL,*now=NULL,*current;
now=(struct ListNode *)malloc(sizeof(struct ListNode ));
current=head=now;
scanf("%d",¤t->data);
if(current->data==-1) return NULL;
while(current->data!=-1){
now=(struct ListNode *)malloc(sizeof(struct ListNode ));
scanf("%d",&now->data);
if(now->data==-1){
current->next=NULL;
break;
}
else{
current->next=now;
current=current->next;
}
}
return head;
}
struct ListNode *deleteeven( struct ListNode *head )//3
{
struct ListNode * p=head,q;
if(head==NULL)return NULL;
while(head && head->data%2==0){ //保证头结点不是偶数
head = head->next; //head->data%2==0&&head这样判断会出现段错误,好奇怪..
}//外层循环判断到结尾,内层循环连续删除
p = head;
while(p && p->next){
while(p->next && p->next->data%2==0){
p->next = p->next->next;
}
p = p->next;
}
return head;
}