Note how to do it.

注意看怎么做。

youdao

Note the caching is not really required for the particular traversal algorithm you are using, but I leave it in to show how to do this if it is needed as you expand this tool in the future.

注意，这个缓存对于您使用的特定遍历算法并不真正需要，我在这里使用它只是为了展示当您将来需要扩展这个工具时应该怎样做。

youdao