请牢记检测回文串的模板

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     struct ListNode *next;
 * };
 */
bool isPalindrome(struct ListNode* head) {
   int size=0;
   struct ListNode* point=head;
   while(point)
   {
       size++;
       point=point->next;
   }
   int arr[size];
    int num = 0;
    while(head)
    {
        arr[num++]= head->val;
        head = head->next;
    } 
    int kuai = num - 1;
    int man = 0;
    while(man < kuai)
    {
        if(arr[man] != arr[kuai])
        {
            return false;
        }
        man++;
        kuai--;
    } 
    return true;     
}