Your welcome! Glad that you liked kata!

Thank you for the engaging challenge. Although it took me many hours to solve, the process was highly enjoyable, and I gained valuable insights. In total, I went through seven iterations. I am a self taught beginner.

I agree with mickey78243; should be rated as an 8kyu

Thanks, I really appreciate your help!

( std::count (seq.begin(), seq.end(), elem) > 0? true: false) can change std::count (seq.begin(), seq.end(), elem) because 0=false any nonzero number =true