class Solution {
    public boolean isPalindrome(ListNode head) {
        if(head==null || head.next==null)
        {
            return true;
        }
        ListNode r=rev(head);
        while(head!=null && r!=null)
        {
            if(head.val!=r.val)
            {
                return false;
            }
            head=head.next;
            r=r.next;
        }
        return true;
    }
    public ListNode rev(ListNode head)
    {
        if(head==null || head.next==null)
        {
            return head;
        }
        ListNode a=rev(head.next);
        head.next.next=head;
        head.next=null;

        return a;
    }
}