数据结构的练习day2(未完待续)

数据结构线性结构之单向循环链表的基本操作

/********************************************************************************************************
 *
 *
 * 设计单向循环链表的接口
 *
 *
 *
 * Copyright (c)  2023-2024   [email protected]   All right Reserved
 * ******************************************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

// 指的是单向循环链表中的结点有效数据类型，用户可以根据需要进行修改
typedef int DataType_t;

// 构造单向循环链表的结点,链表中所有结点的数据类型应该是相同的
typedef struct CircularLinkedList
{
	DataType_t data;								 // 结点的数据域
	struct CircularLinkedList *next; // 结点的指针域

} CircLList_t;

// 遍历链表
bool CircLList_Print(CircLList_t *Head)
{
	// 对单向循环链表的头结点的地址进行备份
	CircLList_t *Phead = Head;

	// 判断当前链表是否为空，为空则直接退出
	if (Head->next == Head)
	{
		printf("current linkeflist is empty!\n");
		return false;
	}

	// 从首结点开始遍历
	while (Phead->next)
	{
		// 把头结点的直接后继作为新的头结点
		Phead = Phead->next;
		// 输出头结点的直接后继的数据域
		printf("data = %d\n", Phead->data);

		// 判断是否到达尾结点，尾结点的next指针是指向首结点的地址
		if (Phead->next == Head->next)
		{
			break;
		}
	}

	return true;
}
// 创建一个空单向循环链表，空链表应该有一个头结点，对链表进行初始化
CircLList_t *CircLList_Create(void)
{
	// 1.创建一个头结点并对头结点申请内存
	CircLList_t *Head = (CircLList_t *)calloc(1, sizeof(CircLList_t));
	if (NULL == Head)
	{
		perror("Calloc memory for Head is Failed");
		exit(-1);
	}

	// 2.对头结点进行初始化，头结点是不存储数据域，指针域指向自身，体现“循环”思想
	Head->next = Head;

	// 3.把头结点的地址返回即可
	return Head;
}

// 创建新的结点，并对新结点进行初始化（数据域 + 指针域）
CircLList_t *CircLList_NewNode(DataType_t data)
{
	// 1.创建一个新结点并对新结点申请内存
	CircLList_t *New = (CircLList_t *)calloc(1, sizeof(CircLList_t));
	if (NULL == New)
	{
		perror("Calloc memory for NewNode is Failed");
		return NULL;
	}

	// 2.对新结点的数据域和指针域进行初始化
	New->data = data;
	New->next = NULL;

	return New;
}

// 头插
bool CircLList_HeadInsert(CircLList_t *Head, DataType_t data)
{
	if (Head == NULL)
	{
		printf("链表为空!\n");
		return false;
	}
	// 创建一个指针代替Head
	CircLList_t *phead = Head;
	// 新建一个结点
	CircLList_t *newNode = CircLList_NewNode(data);
	// 让新建的结点指向原来的首结点
	newNode->next = phead->next;
	// 让头结点指向新建的结点
	phead->next = newNode;
	return true;
}

// 尾插
bool CircLList_TailInsert(CircLList_t *Head, DataType_t data)
{
	if (Head == NULL)
	{
		printf("链表为空!\n");
		return false;
	}
	// 创建一个指针代替Head
	CircLList_t *phead = Head->next;
	// 新建一个结点
	CircLList_t *newNode = CircLList_NewNode(data);

	while (phead->next != Head)
	{
		phead = phead->next;
		if (phead->next == Head->next)
		{
			break;
		}
	}
	//  尾结点指向新结点
	phead->next = newNode;
	// 新结点指向首结点
	newNode->next = Head->next;
	return true;
}

// 指定位置插入(后插)
bool CircLList_DestInsert(CircLList_t *Head, DataType_t destval, DataType_t data)
{
	if (Head == NULL)
	{
		printf("链表为空!\n");
		return false;
	}
	// 创建一个指针代替Head
	CircLList_t *phead = Head;
	// 新建一个结点
	CircLList_t *newNode = CircLList_NewNode(data);
	while (phead)
	{
		// 找到目标结点的上前结点
		if (phead->next->data == destval)
		{
			break;
		}
		phead = phead->next;
	}
	newNode->next = phead->next;
	phead->next = newNode;
}

// 头删
bool CircLList_HeadDel(CircLList_t *Head)
{
	// 对单向循环链表的首结点的地址进行备份
	CircLList_t *Phead = Head->next;
	while (Phead->next != Head)
	{
		if (Phead->next == Head->next)
		{
			break;
		}
		Phead = Phead->next;
	}
	Phead->next = Head->next->next;
	Phead = Head->next;
	Head->next = Head->next->next;
	Phead->next = NULL;
	free(Phead);
	return true;
}

// 尾删
bool CircLList_TailDel(CircLList_t *Head)
{
	// 对单向循环链表的首结点的地址进行备份
	CircLList_t *phead = Head->next;
	// 找到尾结点的前一个结点
	while (phead->next->next != Head)
	{
		if (phead->next->next == Head->next)
		{
			break;
		}
		phead = phead->next;
	}
	phead->next->next = NULL;
	free(phead->next);
	phead->next = Head->next;

	return true;
}

// 指定数据的结点删除(后删)
bool CircLList_DestDes(CircLList_t *Head, DataType_t destval)
{
	// 对单向循环链表的首结点的地址进行备份
	CircLList_t *phead = Head->next;
	// 前结点
	CircLList_t *preNode = Head;
	// 要删除的结点
	CircLList_t *delNode = Head->next;
	while (phead->next != Head)
	{
		if (delNode->data == destval)
		{
			break;
		}
		preNode = delNode;
		delNode = delNode->next;
	}
	preNode->next = delNode->next;
	delNode->next = NULL;
	free(delNode);
	return true;
}
int main(int argc, char const *argv[])
{
	CircLList_t *Head = CircLList_Create();

	CircLList_HeadInsert(Head, 40);
	CircLList_HeadInsert(Head, 30);
	CircLList_HeadInsert(Head, 20);
	CircLList_HeadInsert(Head, 10);

	CircLList_TailInsert(Head, 50);
	CircLList_DestInsert(Head, 30, 15);
	CircLList_HeadDel(Head);
	CircLList_Print(Head);
	CircLList_TailDel(Head);
	CircLList_DestDes(Head, 20);
	CircLList_Print(Head);
	return 0;
}