Atto Trading Technologies Senior Software Engineer C++ interview questions

Brief call with the HR person for intro and background, followed by a take-home assignment that takes about 5 to 8 hours minimum to complete, several red flags on the assignment made me fear that the purpose of the task was not to evaluate the candidate but to solve the company's own problems, the flags: - Make the code cross compile for windows and linux, for an already big task this is a ridiculous request. - Oddly specific requirements that only make sense for a production environments. After I submited the task, and after 2 weeks I got a lazy response that the solution "was not up to the standards", without any specific reason or technical justification, not even a short sentence. I have all the reasons to suspect that the company is not serious, and is just taking advantage from candidate's work to solve their technical problems. Do not fall from this trap and instead ask for an interview with an actual engineer before doing any kind of work for them.