Perguntas de entrevista de vagas de Software Engineer, New Grad da empresa SendGrid

the feedback of the interview process is slow. Interview started with walking through resume. OO terminologies. then a coding problem on collabedit. I solved it and gave a production code in the first attempt without any hint. I was asked to improve the solution. I improved it and then again gave a production code. The interviewer was satisfied. Still i got rejected.