Microsoft Summer Intern - Software Engineer interview questions

Got to their virtual onsite. One of the interviewers was not engaged in seeing my solution to the technical problem. We agreed on the algorithm before I went to actually code it, and he wasn't aware of what/how my code was doing things. I finished the coding he quickly looked at it and accepted the code. Rejected without feedback, I literally have no idea how to improve for next time, thanks for wasting my time in the interviews Microsoft!