Duolingo Software Engineer(Internship) interview questions

Advanced to the final round, which was one 1-hour technical interview followed by an informal 15-minute "buddy chat" Before the interview, I also had to sign an NDA and provide references from past employers

codesignal gca oa (used past score, 600/600) -> karat outsourced interview, 1 hour, 10 minutes of trivial short answer questions about time complexity and the bug and explaining what code does, 50 min hard implementation problem with hashmaps -> batch day final round, 60 minute technical with writing/explaining test cases for a leetcode style problem, solving it, then follow up questions including some oop follow ups (finished in 30 min, talked with interviewers about duolingo for 30 min), 15 minute behavioral with batch day buddy -> call to offer two days later overall a very good process, enjoyed my interviews