import java.util.Stack;

public class Palindrome {
    public boolean isPalindrome(ListNode pHead){
        ListNode fast = pHead;
        ListNode slow = pHead;
        Stack<Integer> stack = new Stack<Integer>();
        while(fast != null && fast.next != null){
            stack.push(slow.val);
            slow = slow.next;
            fast = fast.next.next;
        }
        if (fast != null) {
            slow = slow.next;
        }
        while(slow != null){
            if (stack.pop() != slow.val) {
                return false;
            }
            slow = slow.next;
        }
        return true;
    }
}