【数据结构】线性表链式存储结构-循环链表

• 循环单链表将尾结点next指针域指向头结点
• 循环双链表将尾结点next指针指向头结点，头结点的prior指针指向尾结点
• 可通过p->next ==L来判断尾结点，双向链表可以通过L->prior来找到尾结点

循环链表应用实例

//宏定义
#define FAILED		1
#define SUCCESS		0

typedef struct CirSLinkNode
{
	int data;
	struct CirSLinkNode* next;
}CirSLinkNode;

typedef struct CirDLinkNode
{
	int data;
	struct CirDLinkNode* next;
	struct CirDLinkNode* prior;
}CirDLinkNode;

//带头结点的循环单链表，统计其data域值为x的结点个数

int CountCirSLinkList(CirSLinkNode* L,int x)
{
	CirSLinkNode* p = L->next;
	int i = 0;
	while (p!=L)
	{
		if (p->data ==x)
			i++;
		p = p->next;
	}
	return i;
}

//删除双向循环链表中值为x的第一个元素

int DelCirDLinkList(CirDLinkNode* L,int x)
{
	CirDLinkNode* p = L->next;
	while (p!=L &&p->data !=x)
		p = p->next;
	if (p == L)   FAILED;
	p->next->prior = p->prior;
	p->prior->next = p->next;
	free(p);
	return SUCCESS;
}

//判断带头结点的双向循环链表（带有至少两个结点）是否对称
int SymCirDLinkList(CirDLinkNode* L)
{
	CirDLinkNode* h = L->next;
	CirDLinkNode* r = L->prior;
	int isSame = 1;
	while (isSame)
	{
		if (h->data != r->data)
			isSame = 0;
		else
		{
			if ((h->next == r->prior) || (h == r->prior)) break;
			h = h->next;
			r = r->prior;
		}
	}
	return  isSame;
}