双向链表的实现

Posted 2022-02-06 *insist

不一一介绍了 直接上代码

目录

初始化

创建结点

打印链表

头插

尾插

头删

尾删

定向插入（分前后）

查找

删除

修改

初始化

struct ListNode* InitDlist()//双向链表的初识化

	struct ListNode* pHead=BuyDList(0);
	pHead->next = pHead;
	pHead->prev = pHead;
	return pHead;

创建结点

struct ListNode* BuyDList(DlistType x)//创建新结点 

	struct ListNode* newnode = (struct ListNode*)malloc(sizeof(struct ListNode));
	newnode->prev = NULL;
	newnode->next = NULL;
	newnode->val = x;
	return newnode;

打印链表

void printDlist(struct ListNode* head)//打印

	struct ListNode* next = head->next;
	while (next != head)
	
		printf("%d->", next->val);
		next = next->next;
	
	printf("over\\n");

头插

void PushFront(struct ListNode* head, DlistType x)//头插

	struct ListNode* newnode = BuyDList(x);//创建新结点 
	struct ListNode* first = head->next;//保存除哨兵位的第一个存有数据的结点
	newnode->next =first;//四步操作让新节点插入原链表 两个方向都是双向 方向要变换四次
	newnode->prev = head;
	head->next = newnode;
	first->prev = newnode;
	

头删

void PopBack(struct ListNode* head)//尾删

	assert(head);
	assert(head->next!=head);
	struct ListNode* tail = head->prev;
	struct ListNode* tailprev = tail->prev;
	free(tail);
	tailprev->next = head;
	head->prev = tailprev;

尾插

void PushFront(struct ListNode* head, DlistType x)//头插

	struct ListNode* newnode = BuyDList(x);//创建新结点 
	struct ListNode* first = head->next;//保存除哨兵位的第一个存有数据的结点
	newnode->next =first;//四步操作让新节点插入原链表 两个方向都是双向 方向要变换四次
	newnode->prev = head;
	head->next = newnode;
	first->prev = newnode;
	

尾删

void PopBack(struct ListNode* head)//尾删

	assert(head);
	assert(head->next!=head);
	struct ListNode* tail = head->prev;
	struct ListNode* tailprev = tail->prev;
	free(tail);
	tailprev->next = head;
	head->prev = tailprev;

定向插入（前）

void DListInsertFront(struct ListNode* head, DlistType x, DlistType k)//指定位置前插

	assert(head);
	struct ListNode* insert = FindNode(head, x);
	if (insert)
	
		struct ListNode* newnode = BuyDList(k);
		struct ListNode* prev = insert->prev;
	
		prev->next = newnode;
		newnode->prev = prev;
		newnode->next = insert;
		insert->prev = newnode;
	

定向插入（后）

void DListInsertBehind(struct ListNode* head, DlistType x, DlistType k)//指定位置后插

	assert(head);
	struct ListNode* insert = FindNode(head, x);
	if (insert)
	
		struct ListNode* newnode = BuyDList(k);
		struct ListNode* next = insert->next; 
			newnode->val = k;
		newnode->next = next;
		next->prev = newnode;
		newnode->prev = insert;
		insert->next = newnode;

	

删除

void DListErase(struct ListNode* head, DlistType x)//删除指定结点

	assert(head);
	assert(head->next != head);
	struct ListNode* erase = FindNode(head, x);
	if (erase)
	
		struct ListNode* next = erase->next;
		struct ListNode* prev = erase->prev;
		free(erase);
		next->prev = prev;
		prev->next = next;

	

修改

void DListModify(struct ListNode* head, DlistType x, DlistType k)

	assert(head);
	struct ListNode* modify = FindNode(head, x);
	modify->val = k;

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