1,先找到中间节点,
2.从中间节点以后开始逆置
3.然后从中间节点向后迭代
4.如果是回文,返回true,否则返回false
5.欢迎大家访问我的博客,我也会分享我自己的学习之路
https://blog.csdn.net/m0_63111921/article/details/122463378?spm=1001.2014.3001.5501 
/*
struct ListNode {
    int val;
    struct ListNode *next;
    ListNode(int x) : val(x), next(NULL) {}
};*/
class PalindromeList {
public:
    bool chkPalindrome(ListNode* A) 
    {
        struct ListNode*slow=A;
        struct ListNode*fast=A;
        while(fast->next)
        {
            slow=slow->next;
            fast=fast->next;
        }
        struct ListNode*change=NULL;
        struct ListNode*head=slow;
        while(head)
        {
            struct ListNode*next=slow->next;
            head->next=change;
            change=head;//重新置头
            head=next;
        }
        while(slow)
        {
            if(A->val!=change->val)
            {
                return false;
            }
            slow=slow->next;
            change=change->next;
        }
        return true;
    }
};