链表逆序(链表倒置)

将一个链表按逆序排列，即将链头当链尾，链尾当链头

#include<stdio.h>
struct Node
{
    int data;
    struct Node *next;
};

//创建链表
struct Node *create(int n,int count)
{
    int i;
    struct Node *head,*p1,*p2;
    head = p1 = p2 = (struct Node*)malloc(sizeof(struct Node));
    head->data = n;
    for(i=1; i<count; i++)
    {
        p1 = (struct Node*)malloc(sizeof(struct Node));
        p1->data = i+n;
        p2->next = p1;
        p2 = p1;
    }
    p2->next = NULL;
    return head;
}

//链表逆序(用两个指针跑到后面往前指)
struct Node *reverse(struct Node *p)
{
    struct Node *p1,*p2,*head;
    p1 = p2 = head = p;
    while(p != NULL)
    {
        p = p->next;
        if(p1 == head)
        {
            p1->next = NULL;
        }
        else
        {
            p1->next = p2;
        }
        p2 = p1;
        p1 = p;
    }
    return p2;
}

void main()
{
    struct Node *p,*head;
    //创建链表
    head = p = create(3,5);

    printf("链表初始数据：\n");
    while(p)
    {
        printf("%d\n", p->data);
        p = p->next;
    }

    p = head;

    printf("\n逆转链表：\n");
    p = reverse(p);
    while(p)
    {
        printf("%d\n", p->data);
        p = p->next;
    }
}