I had to complete a HackerRank challenge that was 90 minutes long. It was the Grid Illumination challenge, and I found it pretty challenging. I didn't pass the test cases.
However, the process was still very fun, and I had a great time.
I was only given one question:
Grid Illumination
The following metrics were computed from 19 interview experiences for the Dropbox Software Engineering role in United States.
Dropbox's interview process for their Software Engineering roles in the United States is extremely selective, failing the vast majority of engineers.
Candidates reported having very good feelings for Dropbox's Software Engineering interview process in United States.