Challenge questions in different types of topic for one week. Five questions without grading performance. After I have done it, I didn't receive any feed back for any of the question. DON't apply any position in this company. The interview process is totally waste of time.

There was an initial call. After that, HR sent a problem set. It took about 6 hours to complete 3 problems. Then they gave a tedious reject email without any feedback. Worse, they state that they refuse to provide any feedback or discussion in the email. Generally speaking, if you don't want to waste your time or make yourself upset, then don't take the interview.