Interview here on a weekend is a day long event and an annoying one. They have this hackathon round, where you would be formed in teams with FE & BE and be asked to solve a real world problem, which is fine, but the evaluation in these hackathon is not proper, due to the mass crowd.
Based on the technology they would form teams, for other technologies where the head count is less, they would give you a problem/coding to solve alone, which would mostly be a DS problem, which is definitely not a fair evaluation.