简单双指针
AC Code
import java.util.*;
/*
* public class ListNode {
* int val;
* ListNode next = null;
* }
*/
public class Solution {
/**
*
* @param head ListNode类 the head
* @return bool布尔型
*/
public boolean isPail (ListNode head) {
// write code here
List<ListNode> list = new ArrayList<>();
ListNode node = head;
while(node != null) {
list.add(node);
node = node.next;
}
int size = list.size();
int left = 0, right = size - 1;
while(left < right) {
if(list.get(left).val != list.get(right).val) return false;
left++;
right--;
}
return true;
}
}