百度面经（28）

import java.util.*;
public class Solution {
    public boolean isPail (ListNode head) {
        ArrayList<Integer> nums = new ArrayList();
        //将链表元素取出一次放入数组
        while(head != null){ 
            nums.add(head.val);
            head = head.next;
        }
        //双指针指向首尾
        int left = 0; 
        int right = nums.size() - 1;
        //分别从首尾遍历，代表正序和逆序
        while(left <= right){ 
            //如果不一致就是不为回文
            if(nums.get(left) != nums.get(right)) return false;
            left++;
            right--;
        }
        return true;
    }
}