目录
1.双向链表的结构设计
2.双向链表的结构示意图:
3.双向链表的实现
4.双向链表的总结
1.双向链表的结构设计
typedef struct DNode
{
int data;
struct DNode* next;//后继指针
struct DNode* prio;//前驱指针
}DNode ,*DList;2.双向链表的结构示意图:
3.双向链表的实现
//初始化
void InitList(DList plist)
{
assert(plist != NULL);
if (plist == NULL)
return;
//plist->data不使用
plist->next = NULL;
plist->prio = NULL;
}
//考试重点
//头插
bool Insert_head(DList plist, int val)
{
assert(plist != NULL);
if (plist == NULL)
return false;
//创建新节点
DNode* p = (DNode*)malloc(sizeof(DNode));
assert(p != NULL);
p->data = val;
//插入新节点
p->next = plist->next;//绑线
plist->next = p;
p->prio = plist;
if(p->next!=NULL)//判断很重要
{
p->next->prio = p;
}
return true;
}
//考试重点
//尾插
bool Insert_tail(DList plist, int val)
{
assert(plist != NULL);
if (plist == NULL)
return false;
//创建新节点
DNode* p = (DNode*)malloc(sizeof(DNode));
assert(p != NULL);
p->data = val;
//找尾巴
DNode* q;
for (q = plist; q->next != NULL; q = q->next)
{
;
}
//插入数据
//将p插入到q的后面
p->next = q->next;//p->next=NULL;
p->prio = q;
q->next = p;
return true;
}
//插入数据，在plist链表的pos位置插入val;
bool Insert(DList plist, int pos, int val)
{
assert(plist != NULL);
if (plist == NULL)
return false;
if (pos<0 || pos>GetLength(plist))
{
return false;
}
//申请节点
DNode* p = (DNode*)malloc(sizeof(DNode));
assert(p != NULL);
p->data = val;
//找位置
DNode* q;
int i = 0;
for (q = plist; i < pos; i++, q = q->next)
{
;
}
//插入数据
//将p插入到q的后面
p->next = q->next;
q->next = p;
p->prio = q;
if (p->next != NULL)//判断很重要
{
p->next->prio = p;
}
return true;
}
//判空
bool IsEmpty(DList plist)
{
return plist->next == NULL;
}
//获取数据节点的个数
int GetLength(DList plist)
{
int count = 0;
for (DNode* p = plist->next; p != NULL; p = p->next)
{
count++;
}
return count;
}
//在plist中查找第一个key值，找到返回节点地址，没有找到返回NULL；
DNode* Search(DList plist, int key)
{
for (DNode* p = plist->next; p != NULL; p = p->next)
{
if (p->data == key)
{
return p;
}
}
return NULL;
}
//删除pos位置的值
bool DelPos(DList plist, int pos)
{
assert(plist != NULL);
if (plist == NULL)
return false;
if (pos < 0 || pos >= GetLength(plist))
{
return false;
}
//找位置
DNode* p;
int i;
for (p = plist, i = 0; i < pos; i++, p = p->next)
{
;
}
DNode* q = p->next;//q是要删除的点,注意,q可能是最后一个点
//删除
p->next = q->next;
if (q->next != NULL)
{
q->next->prio = q->prio;//OK
//q->next->prio=p;//OK q->prio就是p
}
//释放
free(q);
return true;
}
//考试重点
//删除第一个val的值
bool DelVal(DList plist, int val)
{
assert(plist != NULL);
if (plist == NULL)
return false;
DNode* p = Search(plist, val);
if (p == NULL)
return false;
p->prio->next = p->next;
if (p->next != NULL)//判断很重要
{
p->next->prio = p->prio;
}
free(p);
return true;
}
//返回key的前驱地址，如果不存在返回NULL；
DNode* GetPrio(DList plist, int key)
{
DNode* p = Search(plist, key);
return p == NULL ? NULL : p->prio;
}
//返回key的后继地址，如果不存在返回NULL；
DNode* GetNext(DList plist, int key)
{
DNode* p = Search(plist, key);
return p == NULL ? NULL : p->next;
}
//输出
void Show(DList plist)
{
for (DNode *p = plist->next; p != NULL; p = p->next)
{
printf("%d ", p->data);
}
printf("\n");
}
//清空数据
void Clear(DList plist)
{
Destroy(plist);
}
//销毁整个内存
void Destroy(DList plist)
{
assert(plist != NULL);
if (plist == NULL)
return;
//总是删除第一个节点
DNode* p;
while (plist->next != NULL)
{
p = plist->next;
plist->next = p->next;
//可以不用处理
/*if (p->next != NULL)
{
p->next->prio = plist;
}*/
free(p);
}
}4.双向链表的总结
双向链表其实和单链表一样,就是把两条方向的单链表都处理好就行.
双向链表的考点就是多级指针,一定要注意判断;
