3 years ago but this is a solution in python. If you want a solution using a different language, check the solution for a different language. Why should you not use an optimal solution in the language you are practicing in just because some other language can't use the same solution? In fact, if this can ONLY be done in python, that makes it more pythonic by definition which is generally considered a plus by most python afficionados.

If we make a concatenation of string is better to declare a "std::stringstream" instead of "std::string"?!?

Why?

excellent advocations

Please use spoiler flag next time.