Stripe Requirements

Quick question about Stripe's process - my brother got rejected last year after the OA with: "Unfortunately, after reviewing your submission, we have decided not to move forward with your candidacy at this time. At Stripe, we are meticulous about our foundations and have a very specific set of skills we are targeting for our University program. This includes a set of core competencies that are built into the HackerRank test that address abilities beyond coding alone." Any ideas what might have been an issue? (Passed testcases, used C++ / longer / explicit variable names, did not comment the code, passed by reference, ...) Is it just boilerplate rejection? #stripe #tech #university