Java 【力扣234】判断回文链表

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution {
    public boolean isPalindrome(ListNode head) {
        ListNode newHead=new ListNode();
        newHead=reverseList(head);
        while (head!=null){
            if(newHead.val!=head.val){
                return false;
            }else {
                head=head.next;
                newHead=newHead.next;
            }
        }
        return true;
    }
    //反转链表
    public ListNode reverseList(ListNode head) {
        if(head==null|| head.next==null){
            return head;
        }
        ListNode dummyHead=new ListNode(-1);
        while (head!=null){
            ListNode node=new ListNode(head.val);
            node.next=dummyHead.next;
            dummyHead.next=node;
            head=head.next;
        }
        return dummyHead.next;
    }
}