双向链表

# include <stdio.h>
# include <malloc.h>
# include <string.h> 
typedef struct node 
{
 struct node *next;
 struct node *prior;
 int data;
}LINK;
int main()
{
 int i,j,k,n,m;
 LINK *q,*p,*tail,*head;
 head=(LINK *)malloc(sizeof(LINK));
 head->next=NULL;
 head->prior=NULL;
 tail=head;
 scanf("%d%d",&n,&m);
 for(i=0;i<n;i++)
 {
  p=(LINK *)malloc(sizeof(LINK));
  scanf("%d",&p->data);
  tail->next=p;
  p->prior=tail;
  tail=p;
 }
 tail->next=NULL;
 while(m--)
 {
  scanf("%d",&j);
  p=head->next;
  for(i=0;i<n;i++)
  {
   if(p->data == j)
   {
    if(p->prior->prior != NULL)
     printf("%d ",p->prior->data);
    if(p->next != NULL)
     printf("%d",p->next->data);
   }
   p=p->next; 
  }
  printf("\n");
 }
 return 0;
}