code: private void buildNode(Node parent, List<String>[] sequence, int from, List<Node> leaf){
          //递归退出条件：二维数组遍历完毕
          if(from >= sequence.length){
              //记住叶子节点
              leaf.add(parent);
              return;
          }
          for(String item : sequence[from]){
              Node child = new Node(item, parent);
              buildNode(child, sequence, from+item.length(), leaf);
          }
      }
docs: 根据全切分中间结果构造切分树
  @param parent 父节点
  @param sequence 全切分中间结果
  @param from 全切分中间结果数组下标索引
  @param leaf 叶子节点集合