回文链表

public static boolean isPalindrome(ListNode head){
        ListNode fast=head;
        ListNode slow=head;
        while (fast!=null&&fast.next!=null){
            slow=slow.next;
            fast=fast.next.next;
        }
        ListNode slowHead=slow;
        ListNode reverse=reverse(slow);
        ListNode h=head;
        while (h!=slowHead){
            if(h.val!=reverse.val){
                return false;
            }
            h=h.next;
            reverse=reverse.next;
        }
        return true;
    }

static ListNode reverse(ListNode head){
        ListNode curr=head;
        ListNode pre=null;
        while (curr!=null){
            ListNode temp=curr.next;
            curr.next=pre;
            pre=curr;
            curr=temp;
        }
        return pre;
    }

@Data
    static class ListNode{
        private int val;
        private ListNode next;

        public ListNode(int value){
            this.val=value;
        }
    }