code: private List<Word> toWords(Node node){
          Stack<String> stack = new Stack<>();
          while(node != null){
              stack.push(node.getText());
              node = node.getParent();
          }
          int len = stack.size();
          List<Word> list = new ArrayList<>(len);
          for(int i=0; i<len; i++){
              list.add(new Word(stack.pop()));
          }
          return list;
      }
docs: 从树叶开始反向遍历生成全切分结果
  @param node 树叶节点
  @return 全切分结果