Had a phone interview last week. Opened with introducing himself and talking about what he does. Then asked me to do the same. Asked about what projects I have worked on and any challenges.

Then he asked me to open the hackerrank and the question was Design Underground System. Explain my thought process as I went along. After finishing he asked about my implementation and why I chose this way of doing things. The code was never ran and we didn't talk about time and space complexity which was strange. Ended by me asking him questions.

Two days later got my onsite invitation