#include<stdio.h>
#include<stdlib.h>struct node
{int data;struct node *next;
};struct node *Creat_List(struct node *head, int n)    //创建链表
{struct node *p;for(int i=0;i<n;i++){p = (struct node *)malloc(sizeof(struct node));scanf("%d",&p->data);p->next = head;head = p;}return head;
}void Put(struct node *head)      //打印链表
{struct node *p;p = head;while(p != NULL){printf("%d ",p->data);p = p->next;}printf("\n");
}struct node* Insert(struct node *head,int k,int num)          //在k处增加元素num
{struct node *p;p = head;for(int i=0;i<k;i++){p = p->next;}struct node *temp;temp = (struct node *)malloc(sizeof(struct node));temp->data = num;temp->next = p->next;p->next = temp;return head;
}struct node *Delete(struct node *head, int k)
{struct node *p;p = head;for(int i=1;i<k-1;i++){p = p->next;}struct node *temp;temp = p->next;p->next = temp->next;return head;
}bool Find(struct node *head,int num)
{struct node *p;p = head;while(p != NULL){if(p->data == num){return true;}p = p->next;}return false;
}struct node *Change(struct node *head,int k,int num) //将数字k改为num
{struct node *p;p = head;while(p!=NULL){if(p->data == k){p->data = num;}p = p->next;}return head;
}int main()
{int n;                  //链表长度scanf("%d",&n);struct node *head=NULL;head = Creat_List(head, n);Put(head);head = Insert(head,2,1000);//Put(head);head = Delete(head,4);//Put(head);head = Change(head,4,6);//Put(head);bool ok = Find(head,7);if(ok)printf("yes\n");elseprintf("no\n");return 0;
}