I had a similar experience my first time, but I applied again a year later and passed. I did study algorithms (mostly DP and graph stuff) via HackerRank for two

I had a similar experience my first time, but I applied again a year later and passed. I did study algorithms (mostly DP and graph stuff) via HackerRank for two weeks before each onsite, but I never did fully succeed with any of the algorithms questions. The second time, I think I was just lucky with questions I liked. I don't think my programming ability changed drastically in the year between.