Can I insert the advertisement on sololearn code playground?

Answer 1

In SoloLearn rules, the only part that can be associated to your question could be the prohibition to use "unauthorised content".
Afaik this is the only answer you can get in Q&A.
Try sending an email to SL and ask them permission for what you want to do.
That will be the definitive answer.

Answer 2

No , why you need advertisement

Answer 3

how bout... no.