试编写算法将带头结点的单链表就地逆置，所谓“就地”是指空间复杂度为 O(1)。

#include <iostream>
using namespace std;


typedef int Elemtype;
#define ERROR 0;
#define OK    1;

typedef struct LNode
{
	Elemtype data;      //结点保存的数据
	struct LNode* next; //结构体指针
}LNode, * LinkList;

/*单链表初始化*/
bool Init_LinkList(LinkList& L)
{
	L = (LinkList)malloc(sizeof(LNode));  //新建头结点
	if (L == NULL)
	{
		return ERROR;
	}
	L->data = 0;
	L->next = NULL;
	return OK;
}
/*单链表头插法*/
bool LinkList_head_instert(LinkList& L)
{
	int x = 0;
	LNode* p = NULL;
	while (cin >> x)
	{
		p = (LinkList)malloc(sizeof(LNode));
		if (p != NULL)  //防止分配地址失败
		{
			p->data = x;
			p->next = L->next;
			L->next = p;
			if (cin.get() == '\n') break;  //检测换行符
		}
		else
		{
			exit(0);
			cout << "内存分配失败" << endl;
		}
	}
	return OK;
}
/*单链表尾插法*/
bool LinkList_tail_instert(LinkList& L)
{
	int x = 0;
	LNode* p = NULL;
	LNode* r = NULL;
	r = L;
	while (cin >> x)
	{
		p = (LinkList)malloc(sizeof(LNode));
		if (p != NULL)  //防止分配地址失败
		{
			p->data = x;
			p->next = NULL;
			r->next = p;
			r = p;
			if (cin.get() == '\n') break;  //检测换行符
		}
		else
		{
			exit(0);
			cout << "内存分配失败" << endl;
		}
	}
	return OK;
}

/*单链表遍历*/
bool LinkList_All_value(LinkList L)
{
	if (L->next == NULL)
	{
		cout << "链表为空" << endl;
		return ERROR;
	}
	LNode* s = NULL;
	s = L->next;
	while (s != NULL)
	{
		cout << s->data << "   ";
		s = s->next;
	}
	cout << endl;
	free(s);
	return OK;
}

/*单链表长度*/
int LinkList_length(LinkList L)
{
	int count = 0;
	LNode* s = NULL;
	s = L->next;
	while (s != NULL)
	{
		count++;
		s = s->next;
	}
	return count;
}

/*清空单链表*/
void Clear_LinkList(LinkList& L)
{
	LNode* p = L->next;
	LNode* q = NULL;
	while (p != NULL)
	{
		q = p->next;
		free(p);
		p = q;
	}
	L->next = NULL;
}

/*销毁单链表*/
void Destory_LinkList(LinkList& L)
{
	LNode* p = NULL;
	LNode* q = NULL;
	p = L;
	while (p != NULL)
	{
		q = p->next;
		free(p);
		p = q;
	}
	L = NULL;
}

//-----------------------------------------核心代码-----------------------------------------//
bool reverse(LinkList &L)
{
	LNode* p = NULL;
	LNode* r = NULL;
	p = L->next;
	if (L->next == NULL)
	{
		cout << "单链表数据为空!!!" << endl;
		return ERROR;
	}
	L->next = NULL;
	while (p!=NULL)
	{
		r = p->next;
		p->next = L->next;
		L->next = p;
		p = r;
	}
	return OK;
}
//-----------------------------------------核心代码-----------------------------------------//

//试编写算法将带头结点的单链表就地逆置，所谓“就地”是指空间复杂度为 O(1)。
int main(void)
{
	LinkList L1 = NULL;
	Init_LinkList(L1);
	LinkList_tail_instert(L1);//1 2 3 4
	reverse(L1);
	LinkList_All_value(L1);
	return 0;
}