数据结构之双向链表

双向链表（以带头节点的双向链表）的结构如下：

由数据域，指向后继的指针，以及纸箱前驱的指针构成。

1. 该双向链表的定义如下：

typedef struct  DNode{    int data;//数据域   struct DNode *next;//指向后继   struct DNode *prio;//指向前驱}DNode ,*DList;

2. 双向链表的初始化

void InitList(DList plist){plist->next = NULL;plist->prio = NULL;}

3. 利用头插法插入

bool Insert_Head(DList plist,int val){DNode *p = (DNode *)malloc(sizeof(DNode));p->data = val;p->next = plist->next;//1plist->next = p;//2p->prio = plist;if(p->next != NULL)//特殊情况,p是第一次插入的节点{p->next->prio = p;}return true;}

4. 利用尾插法插入

bool Insert_Tail(DList plist,int val){DNode *p = (DNode *)malloc(sizeof(DNode));p->data = val;DNode *q;for(q=plist;q->next!=NULL;q=q->next) ;//将p插在q的后面q->next = p;p->prio = q;p->next = NULL;return true;}

5. 按关键字查找

DNode *Search(DList plist,int key){for(DNode *p=plist->next; p!=NULL; p=p->next){if(p->data == key){return p;}}return NULL;}

6. 按关键字删除

bool Delete(DList plist,int key){DNode *p = Search(plist,key);if(p == NULL){return false;}p->prio->next = p->next;if(p->next != NULL)//p为尾节点{p->next->prio = p->prio;}free(p);return true;}

7. 判空

bool IsEmpty(DList plist){if (plist->next==NULL && plist->prio==NULL){return true;}else{return false;}}

8. 求长

int GetLength(DList plist){int count = 0;for (DNode *p=plist->next; p!=NULL; p=p->next){count ++;}return count;}

9. 打印链表

void Show(DList plist){for (DNode *p=plist->next; p!=NULL; p=p->next){printf("%d  ", p->data);}printf("\n");}

10. 清楚链表

void Clear(DList plist){Destroy(plist);}

11. 摧毁链表

void Destroy(DList plist){DNode *p;while(plist->next != NULL){p = plist->next;plist->next = p->next;free(p);}}