They send you a HackerRank link to solve a couple of "easy" problems in 90 minutes. One of the problems was harder than expected, but after a couple of tries I managed to solve it with an efficient algorithm and pass all tests. Took about 45 minutes in total. After that they contacted me to inform that I was not selected because other candidates reached a higher score in the challenge. I think they should be more clear about what they expect from this first test. I am more used to initial screenings to be not so strict and just tried not to over-do it. Turns out that's what they expected me to do. Not a good practice to hire, IMHO. You are filtering perfectly good candidates that might excel in solving real-world problems just because they didn't get a perfect score in a particular mathematical problem.