题解 | #链表的回文结构#

import java.util.*;

/*
public class ListNode {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}*/
public class PalindromeList {
    public boolean chkPalindrome(ListNode head) {
        // write code here
        ListNode fast = head;
        ListNode slow = head;
        while(fast != null && fast.next != null){
            fast = fast.next.next;
            slow = slow.next;
        }
        ListNode cur = slow;
        while(cur != null){
            ListNode curN = cur.next;
            cur.next = slow;
            slow = cur;
            cur = curN;
        }
        while(head != slow){
            if(head.val == slow.val){
                head = head.next;
                slow = slow.next;
            } else {
                return false;
            }
            if(head.next == slow){
                return true;
            }
        }
        return true;
    }
}