I'll give you "the complexity of your algorithm" likely doesn't change, but how that algorithm is processed is usually more efficient when compiled through C, rather than running through a Python interpreter, if only because of how it's running.
Saying "my code is more efficient than your code" might be acceptable, but saying "my code is efficient" drives me mad when it is used as a synonym for "my code is fast". Take a look at [1] and the note that this is not about optimization. Efficient algorithms are usually algorithms with close to optimal time or space complexitiy.