判断一个链表是否为回文结构

 

using System;
using System.Collections;
using System.Collections.Generic;


public class ListNode
{
    public int val;
    public ListNode next;

    public ListNode (int x)
    {
        val = x;
    }
}


class Solution
{
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param head ListNode类 the head
     * @return bool布尔型
     */
    public bool isPail(ListNode head)
    {
        // write code here
        if (head == null)
        {
            return true;
        }
        Stack<ListNode> stackNode = new Stack<ListNode>();

        ListNode moveNode = head;
        while (moveNode != null)
        {
            stackNode.Push(moveNode);
            moveNode = moveNode.next;
        }

        moveNode = head;

        while (moveNode != null)
        {
            ListNode popNode = stackNode.Pop();
            if (popNode.val != moveNode.val)
            {
                return false;
            }
            moveNode = moveNode.next;
        }
        return true;

    }
}