The overall interview process went well in the beginning. I have been contacted by recruiter, then talked to hiring manager. Given the mutual interest we have moved forward with the application. I have received a take home assignment. It was protein and ligand binding problem from drug discovery. Unfortunately they have not given the data itself, I had to dig it out from the internet. After 4 full days working on the problem, I have managed to find the data, build a predictive model using AI tools and Google Cloud computation. The problem was not an easy to solve, I had to add compute power to it. After that I have send the solution to my friend, one Data Science director and one Computational Research scientists. They both gave me feedback, which I have incorporated, made nice presentation. Overall it felt like 1 week of work, rather than 4 days. I was working non-stop for 12 hours a day. After submission I have been given the response that I did not pass. Without any explanation whatsoever, no clear message, no discussion. It was basically a huge waste of my time and skills, while I have solved the problem. Yet as recruiter said "it was not up to the standard", while the standard has never been clearly described to me. So, my advice for the potential employees - do not waste your time, there are better companies that offer stock and value candidates time more. My advice for the employer - do not ask for long take home assignment, it should take no more than 1 day solve, otherwise it will be a waste of time for candidates.