求助高手：怎么样把一个链表倒置呢？

[hualuchi]

求助高手：怎么样把一个链表倒置呢？

[wuyu637]

以前csdn上的代码，重贴一下
#include <iostream>
using namespace std;

class node
{
public:
node(int x):data(x),next(0){}
int data;
node* next;
};

node* ReverseList(node* head)
{
node* p=0;
node* q=head; // now q is the head of new list
while(head->next!=0) // head node is always the same, but its next node will change
{
p=head->next; // get the next node, it is the current node
head->next=p->next; // set the head->next to the next node, using in next loop
p->next=q; // make the current node pointer the head of new list
q=p; // set the q as the head of new list
}
return q; // now q is the head of new list
}

int main()
{
node* head=new node(0);
node* tail=head;
for(int i=1;i<10;i++)
{
node* p=new node(i);
tail->next=p;
tail=p;
}
head=ReverseList(head);
while (head)
{
cout<<head->data<<endl;
head=head->next;
}
getchar();
return 0;
}

[adventurelw]

用反向迭代器。

[luxiaoxun]

void Reverse(List & L)
{
  List p=L->next;  	// 原链表
  L->next=NULL;  	// 新表(空表)
  while ( p ) 
  {
    // 从原链表中取下结点s
    List s=p;
    p=p->next;
    // 插入L新表表头
    s->next=L->next;
    L->next=s;
  }
}

[hualuchi]

谢谢…………

[小y正在思考人生]

反向建立一新链表不就得了.....

[cxf7394373]

void Reverse(List & L)
{
List p=L->next; // 原链表
L->next=NULL; // 新表(空表)
while ( p )
{
// 从原链表中取下结点s
List s=p;
p=p->next;
// 插入L新表表头
s->next=L->next;
L->next=s;
}
}

[十八道胡同]

node*  ReverseList(node*  head)  
  {  
          node*  p=0;  
          node*  q=head;                              //  now  q  is  the  head  of  new  list  
          while(head->next!=0)                //  head  node  is  always  the  same,  but  its  next  node  will  change  
          {  
                  p=head->next;                      //  get  the  next  node,  it  is  the  current  node  
                  head->next=p->next;          //  set  the  head->next  to  the  next  node,  using  in  next  loop  
                  p->next=q;                            //  make  the  current  node  pointer  the  head  of  new  list  
                  q=p;                                        //  set  the  q  as  the  head  of  new  list  
          }  
          return  q;                                      //  now  q  is  the  head  of  new  list  
  }  
  

[foolloow]

笔试时考到了，当时写的比较乱，这个很清楚。

[alicktony]

其实最简洁应该是递归

[某某9]

Node* LinkList_reverse(Node* head)

{

	Node *preNode,*curNode,*nextNode;  

	if(head==NULL) return NULL;//空链表

	if(head->next == NULL) return head;//仅一个元素  

	curNode = head;preNode=NULL;//初始化  

	while(curNode)

	{

		nextNode = curNode->next;//先记录下一个结点

		curNode->next = preNode;//改变链表方向（逆置）

		preNode = curNode;//将当前结点作为下一次循环的前一个结点

		curNode = nextNode;//向后推移一个结点

	}  

	return preNode;//当遍历完链表后curNode应该为空，此时preNode就是逆置后链表头(head)  
}  

[cheng_fengming]

原来写的单链表逆序的例子

#include<stdio.h>
#include<malloc.h>
#define LEN sizeof(struct stru)

struct stru
{
	int num;
	struct stru *next;
};
typedef struct stru pNode;

int n;
pNode *create_list();
void print_list(pNode *head);
pNode *reverse_list(pNode *head);

void main()
{
	pNode *head = NULL, *newhead = NULL;
	printf("Creating the list,input the num(end of string):\n");
	head = create_list();
	printf("The original list is:\n");
	print_list(head);
	newhead = reverse_list(head);
	printf("\nThe new list is:\n");
	print_list(newhead);
}

pNode *reverse_list(pNode *head)
{
	int i;
	pNode *p1, *p2, *newhead, *newp;
	for (i = 0; i <= n; i++)
	{
		p2 = p1 = head;
		while (p1->next != NULL)
		{
			p2 = p1;
			p1 = p1->next;
		}
		if (i == 0)
		{
			newhead = newp = p1;
		}
		else
		{
			newp = newp->next = p1;
			p2->next = NULL;
		}
	}
	return (newhead);
}

其他的函数定义没有贴上来，省地方，呵呵