环形链表操作实现-优快云博客

本文介绍了一种环形链表的数据结构实现方法，并提供了包括插入、删除等基本操作在内的多个函数定义。此外，还通过两个示例展示了如何利用这些函数进行环形链表的操作，如约瑟夫环问题。

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环形链表.h

#include<stdio.h>
#include<stdlib.h>

struct info
{
	int data;
	struct info *pNext;
};

typedef struct info node, *PNODE;

PNODE addBack(PNODE phead, int data);	//尾部插入
PNODE addFront(PNODE phead, int data);	//头部插入
PNODE findFirst(PNODE phead, int data);	//检索数据
PNODE deleteFirst(PNODE phead, int data);	//删除数据

PNODE deleteNode(PNODE phead, int data,PNODE *ptemp);	//删除数据

PNODE insertNode(PNODE phead, int finddata, int data);	//插入数据
int getNum(PNODE phead);	//返回链表的个数
void showAll(PNODE phead);	//显显示全部

环形链表.c


#include"环形链表.h"

PNODE addBack(PNODE phead, int data)	//尾部插入
{
	node *pnew = malloc(sizeof(struct info));	//分配内存
	pnew->data = data;

	if (phead == NULL)
	{
		phead = pnew;
		phead->pNext = pnew;
	}
	else
	{
		PNODE p = phead;
		while (p->pNext != phead) //循环到尾部
		{
			p = p->pNext;
		}
		p->pNext = pnew;
		pnew->pNext = phead; //头尾相连
		
	}

	return phead;
}
PNODE addFront(PNODE phead, int data)	//头部插入
{
	node *pnew = malloc(sizeof(struct info));	//分配内存
	pnew->data = data;

	if (phead == NULL)
	{
		phead = pnew;
		phead->pNext = pnew;
	}
	else
	{
		PNODE p = phead;
		while (p->pNext != phead) //循环到尾部
		{
			p = p->pNext;
		}
		p->pNext = pnew;
		pnew->pNext = phead; //头尾相连
		phead = pnew;
	}

	return phead;
}
void showAll(PNODE phead)	//显显示全部
{
	if (phead == NULL)
	{
		printf("链表为空！\n");
		return;
	}
	else if (phead->pNext == phead)
	{
		printf("%d %p %p\n", phead->data, phead, phead->pNext);	//只有一个节点
	}
	else
	{
		PNODE p = phead;
		while (p->pNext != phead)
		{
			printf("%d %p %p\n", p->data, p, p->pNext);	
			p = p->pNext;
		}
		printf("%d %p %p\n", p->data, p, p->pNext);	//最后一个节点。
	}
}

PNODE findFirst(PNODE phead, int data)	//检索数据
{
	if (phead == NULL)
	{
		return	NULL;
	}
	else if (phead->pNext == phead) //如果头节点是要查询的数据
	{
		return phead;
	}
	else
	{
		PNODE p = phead;
		while (p->pNext != phead)
		{
			if (p->data == data)
			{
				return p; //如果找到返回。
			}
			else
			{
				p = p->pNext;	//找不到继续前进
			}
		}
		if (p->data == data)
			return p;
		return NULL;
	}
}
PNODE deleteFirst(PNODE phead, int data)	//删除数据
{
	//先判断要删除的数据是否存在。
	PNODE p = findFirst(phead, data);
	if (p == NULL)
	{
		printf("没有检索到数据！\n");
		return phead;
	}
	//删除需要使用双指针
	PNODE p1, p2;
	p1 = phead;
	p2 = NULL;
	//上面的判断要使用，否则最后一个不好判断
	while (p1->pNext != phead)
	{
		if (p1->data == data)
		{
			break;
		}
		else
		{
			p2 = p1;
			p1 = p1->pNext;//循环下个节点
		}
	}

	if (p1 != phead)
	{
		p2->pNext = p1->pNext;
		free(p1);
		p1 = NULL;
	}
	else
	{
		node *p = phead;
		while (p->pNext != phead)
		{
			p = p->pNext;
		}

		phead = phead->pNext;	//改变头节点
		free(p1);	//释放p1
		p->pNext = phead;

	}

	//
	//	if (p1->pNext == phead)
	//	{
	//		if (p1->data == data)
	//		{
	//			printf("删除的数据是:%d %p\n", p1->data, p1);
	//			free(p1);
	//			phead = NULL;
	//			return phead;
	//		}
	//	}
	//	else
	//	{		
	//		while (p1->pNext != phead)
	//			{
	//				if (p1->data == data)
	//				{
	//					break;//找到后跳出循环
	//				}
	//				else
	//				{
	//					p2 = p1;
	//					p1 = p1->pNext;
	//				}
	//			}
	//		/* 这儿最后一个数据没有访问到，所以先要用查询，查询一遍 */
	//	}
	//	if (p1 == phead)	//如果是第一个
	//	{
	//		PNODE p = phead;
	//		while (p->pNext != phead)
	//		{
	//			p = p->pNext;	//循环到尾部
	//		}			
	//		phead = phead->pNext;
	//		p->pNext = phead;
	//		printf("删除的数据是:%d %p\n", p1->data, p1);
	//		free(p1);
	//		p1 = NULL;
	//	}
	//	else
	//	{
	//		p2->pNext = p1->pNext;
	//		printf("删除的数据是:%d %p\n", p1->data, p1);
	//		free(p1);
	//	}
		return phead;
	
}


PNODE deleteNode(PNODE phead, int data, PNODE *ptemp)
{
	//先判断要删除的数据是否存在。
	PNODE p = findFirst(phead, data);
	if (p == NULL)
	{
		printf("没有检索到数据！\n");
		return phead;
	}
	//删除需要使用双指针
	PNODE p1, p2;
	p1 = phead;
	p2 = NULL;
	//上面的判断要使用，否则最后一个不好判断
	while (p1->pNext != phead)
	{
		if (p1->data == data)
		{
			break;
		}
		else
		{
			p2 = p1;
			p1 = p1->pNext;//循环下个节点
		}
	}

	if (p1 != phead)
	{
		p2->pNext = p1->pNext;

		*ptemp = p1->pNext;	//指向下个节点
		
		free(p1);
		p1 = NULL;
	}
	else
	{
		node *p = phead;
		while (p->pNext != phead)
		{
			p = p->pNext;
		}

		phead = phead->pNext;	//改变头节点

		*ptemp = p1->pNext;	//指向下个节点

		free(p1);	//释放p1
		p1 = NULL;
		p->pNext = phead;

	}
	return phead;

}

PNODE insertNode(PNODE phead, int finddata, int data)	//插入数据
{
	PNODE pnew = malloc(sizeof(node));
	pnew->data = data;

	PNODE p = findFirst(phead, finddata);
	if (p == NULL)
	{
		printf("没有找到要插入数据的标记！\n");
	
	}
	else
	{
		PNODE p1, p2;
		p1 = phead;
		p2 = NULL;
		while (p1->pNext != phead)
		{
			if (p1->data == finddata)
			{
				break;
			}
			else
			{
				p2 = p1;
				p1 = p1->pNext;
			}
		}
		if (p1 == phead)
		{
			
			PNODE p = phead;
			while (p->pNext != phead)
			{
				p = p->pNext;
			}
			//插在前面
			p->pNext = pnew;
			pnew->pNext = phead;
			phead = pnew;

			//插在后面
		/*	pnew->pNext = phead->pNext;
			phead->pNext = pnew;*/
		}
		else
		{
			//插在前面
			p2->pNext = pnew;
			pnew->pNext = p1;
			//插在后面
			/*pnew->pNext = p1->pNext;
			p1->pNext = pnew;*/
		}
	}

	return phead;
}

int getNum(PNODE phead)	//返回链表的个数
{
	if (phead == NULL)
	{
		return 0;
	}
	else if (phead->pNext == phead)
	{
		return 1;
	}
	else
	{
		int sum = 0;
		PNODE p = phead;
		while (p->pNext != phead)
		{
			sum++;
			p = p->pNext;
		}
		sum++;
		return sum;
	}
}

main.c

#include"环形链表.h"

/* 环形链表的演示 */
void main1()
{
	PNODE phead	= NULL;
	for (int i = 0; i < 10; i++)
	{
		phead = addBack(phead, i);
		//phead = addFront(phead, i);
	}

	//phead = addBack(phead, 88);

	showAll(phead);
	printf("\n\n");
	PNODE p = findFirst(phead, 0);
	p->data = 88;
	showAll(phead);

	phead = deleteFirst(phead, 88);
	printf("\n\n");
	showAll(phead);

	printf("\n环形链表共有：%d 个\n", getNum(phead));

	phead = insertNode(phead, 1, 99);
	printf("\n\n");
	showAll(phead);


	printf("\n环形链表共有：%d 个\n", getNum(phead));



	system("pause");
}

/* 约瑟夫环： 有m个人围成一圈，开始报数，报道n，退出，问最后剩下的是几号。下面是以数到 5 时出局 然后继续数 */
void main()
{
	PNODE phead = NULL;
	for (int i = 0; i < 10; i++)
	{
		phead = addBack(phead, i);
		//phead = addFront(phead, i);
	}

	showAll(phead);

	PNODE p = phead;
	while (getNum(phead) != 1)
	{
		for (int i = 0; i < 4; i++)
		{
			p = p->pNext; 
		}
		//删除后需要让 p 指向下个节点，所以这儿使用了 &p.
		phead = deleteNode(phead, p->data, &p);
		
		printf("\n\n");
		showAll(phead);
	}


	system("pause");
}