Preguntas de entrevista para el puesto de Developer Java Python en Fivetran

First round coding on Java Basic questions, not at all difficult, just wanted to check OOPS concept. Second round : Skype interview Gave me three option to choose among A) data structure B) graph theory C) core computers I choose DS, So there was a real time coding round called as code pair. 1 question related to subarray and pointer stuff. Difficulty level : Mid Range