[数据结构与算法]循环链表函数及双向链表

循环链表删除结点

CircleListNode* CircleList_Delete(CircleList* list,int pos)
{
   TCircleList* sList = (TCircleList*)list;
   int i=0;
   if(sList !=NULL)&&(pos>=0)&&(sList ->length >0))
   {
      CircleListNode* current =(CircleListNode*)sList;
      CircleListNode* last = NULL:
      for(int i=0;i<pos;i++)
      {
          current =current ->next;
       }
       //删除头结点
       if( current ==(CircleListNode*)sLIst)
       {
         last = (CircleListNode*)CircleList_Get(sList,sList->length - 1);
         }
         //求要删除的元素
         ret = current ->next;
         current->next =ret->next;
         sList->length--;
         //判断链表是否为空
         if(last !=NULL)
         {
           sList->header.next = ret->next;
           last->next = ret->next;
          }
          //若删除元素后，链表长度为0
          if(sList->Length == 0)
          {
             sList->header.next = NULL;
             sList->slider = NULL;
           }
     }
     return ret;
}
CircleListNode* CircleList_DeleteNode(CircleList* list,CircleListNode* node)
{
   TCircleList* sList = (TCircleList*)list;
   CircleListNode* ret = NULL;
   int i=0;
   if(sList != NULL)
   {
     CircleListNode* current = (CircleListNode*)sList;
//查找node在循环链表的位置
      for(int i=0;i<sList->lengh;i++)
      {
        if(current->next==node)
        {
           ret = current->next;
           break;
         }

         current = current->next;
       }
//找到ret，根据i去删除
       if(ret!=NULL)
       {
          CircleList_Delete(sList,i);
        }
     }
     return ret;
}



CircleListNode* CircleList_Next(CircleList* list)
{
  TCircleList* slist = (TCircleList*)list;
  CircleListNode* ret = NULL;
  if(sList != NULL)&&(sList->slider !=NULL))
  (  
     ret = sList ->slider;
     sList->slider = ret->next;
   }
   return ret;
}

双向链表

单链表数据元素无法直接访问其前驱元素
在单链表的结点中增加一个指向其前驱的pre指针

双向链表拥有单链表的所有操作
创建链表
销毁链表
获取链表长度
清空链表
获取第pos个元素操作
插入元素到位置pos
删除位置pos处的元素

一般实现

current->next = node;
node->next = next;
next->pre = node;
node->pre = current;

删除操作

current->next = next;
next->pre = current;