判断一个链表是否为回文结构

public boolean isPail(ListNode head) {
        ListNode slow = head;
        ListNode fast = head;
        while (fast != null && fast.next != null) {
            fast = fast.next.next;
            slow = slow.next;
        }
        ListNode curr1 = reverse(slow);
        ListNode curr2 = head;
        while (curr1 != null) {
            if (curr1.val!= curr2.val) {
                return false;
            }
            curr1 = curr1.next;
            curr2 = curr2.next;
        }
        return true;
    }

    private ListNode reverse(ListNode node) {
        ListNode prev = null;
        ListNode curr = node;
        while (curr != null) {
            ListNode temp = curr.next;
            curr.next = prev;
            prev = curr;
            curr = temp;
        }
        return prev;
    }