6. 从尾到头打印链表

使用栈

public List<Integer> printListFromTailToHead(ListNode listNode) {
        Stack<Integer> stack = new Stack<>();
        while(null != listNode) {
            stack.push(listNode.val);
            listNode = listNode.next;
        }
        List<Integer> list = new ArrayList<>();
        while (!stack.isEmpty()) {
            list.add(stack.pop());
        }
        return list;
    }