/**********************************************************************************
*
-
file name: 003_单向循环链表.c -
author : [email protected] -
date : 2024/04/23 -
function : 设计单向循环链表的接口 -
note : None -
CopyRight (c) 2024-2024 [email protected] All Right Reseverd - *******************************************************************************/
#include <stdio.h>
#include <stdbool.h>
#include <stdlib.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;
//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)
{
//将传进来的数据创建一个新的节点
CircLList_t *New = CircLList_NewNode(data);
if (NULL == New)
{
printf("can not insert new node\n");
return false;
}
//定义一个变量存储尾节点
CircLList_t *tmp = head->next;
//判断是否为空链表
if (head->next == head)
{
head->next = New;
New->next = New;
return true;
}
//遍历到尾节点
while (tmp->next != head->next)
{
tmp = tmp->next;
}
//将新节点插入头部
New->next = head->next;
tmp->next = New;
head->next = New;
return true;
}
//尾插
bool CircLList_TailInsert(CircLList_t *head,DataType_t data)
{
//将传进来的数据创建一个新的节点
CircLList_t *New = CircLList_NewNode(data);
if (NULL == New)
{
printf("can not insert new node\n");
return false;
}
CircLList_t *tmp = head->next;
//判断是否为空链表
if (head->next == head)
{
head->next = New;
New->next = New;
return true;
}
//遍历到尾节点
while (tmp->next != head->next)
{
tmp = tmp->next;
}
tmp->next = New;
New->next = head->next;
return true;
}
//指定位置插入(找链表中已存在的数据的后面插)
bool CircLList_DestInsert(CircLList_t *head,DataType_t destval,DataType_t data)
{
//将传进来的数据创建一个新的节点
CircLList_t *New = CircLList_NewNode(data);
if (NULL == New)
{
printf("can not insert new node\n");
return false;
}
//判断是否为空链表
if (head->next == head)
{
head->next = New;
New->next = New;
return true;
}
//定义两个变量记录头节点和首节点地址
CircLList_t *tmp1 = head;
CircLList_t *tmp2 = head->next;
while (tmp2->next != head->next)
{
tmp2 = tmp2->next;
tmp1 = tmp1->next;
if (tmp2->data == destval)
{
//指定位置刚好在尾部(后插)
if (tmp2->next == head->next)
{
New->next = tmp2->next;
tmp2->next = New;
New->next = head->next;
return true;
}
New->next = tmp2->next;
tmp2->next = New;
}
else if (tmp1->data == destval)
{
//指定位置刚好在头部(后插)
if (tmp1 == head->next)
{
New->next = tmp1->next;
tmp1->next = New;
return true;
}
}
}
return true;
}
//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;
}
//头删
bool LList_HeadDel(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->next;
CircLList_t *tmp = Head->next;
//链表为空的情况下
if (Head->next == Head)
{
printf("此链表为空！没有元素可以删除!");
return false;
}
//遍历尾节点
while(tmp->next != Head->next)
{
tmp = tmp->next;
}
Head->next = Phead->next;
tmp->next = Phead->next;
Phead->next = NULL;
free(Phead);
return true;
}
//尾删
bool LList_TailDel(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;
CircLList_t *tmp = Head->next;
//链表为空的情况下
if (Head->next == Head)
{
printf("此链表为空！没有元素可以删除!");
return false;
}
//遍历尾节点
while(tmp->next != Head->next)
{
Phead = Phead->next;
tmp = tmp->next;
}
Phead->next = tmp->next;
tmp->next = NULL;
free(tmp);
return true;
}
//指定删
bool CircLList_DestDel(CircLList_t *Head,DataType_t destval)
{
//链表为空的情况下
if (Head->next == Head)
{
printf("此链表为空！没有元素可以删除!");
return false;
}
CircLList_t *tmp1 = Head;
CircLList_t *tmp2 = Head->next;
while (tmp2->next != Head->next)
{
tmp2 = tmp2->next;
tmp1 = tmp1->next;
if (tmp2->data == destval)
{
//指定位置刚好在尾部
if (tmp2->next == Head->next)
{
tmp1->next = tmp2->next;
tmp2->next = NULL;
free(tmp2);
return true;
}
tmp1->next = tmp2->next;
tmp2->next = NULL;
free(tmp2);
}
//指定位置刚好在头部
else if (tmp1->data == destval)
{
if (tmp1 == Head->next)
{
CircLList_t *Phead = Head->next;
// 遍历到尾节点
while (Phead->next != Head->next)
{
Phead = Phead->next;
}
Head->next = tmp1->next;
Phead->next = tmp1->next;
tmp1->next = NULL;
free(tmp1);
return true;
}
}
}
printf("该链表中没有这个数!\n");
}
int main(int argc, char const *argv[])
{
CircLList_t *head = CircLList_Create();
//头插入
CircLList_HeadInsert(head,5);
CircLList_HeadInsert(head,6);
CircLList_HeadInsert(head,7);
CircLList_HeadInsert(head,8);
CircLList_HeadInsert(head,9);
CircLList_Print(head);
//尾插
printf("尾插法:\n");
CircLList_TailInsert(head,55);
CircLList_Print(head);
//指定位置插入(找链表中已存在的数据的后面插)
printf("指定插:\n");
CircLList_DestInsert(head,9,99);
CircLList_DestInsert(head,6,909);
CircLList_DestInsert(head,55,9900);
CircLList_Print(head);
// LList_HeadDel(head);
// LList_TailDel(head);
printf("\n");
CircLList_DestDel(head,9900);
CircLList_DestDel(head,91);
CircLList_Print(head);
return 0;
}