The interview is very long, has 5 steps.
HR, home assignments and then there are some online (live) interviews
You get a home assignment to build a C application to manipulate an image that supposedly takes 4h to create (take note, an old school C application, with Makefile), but it takes much longer if you want it to be quality code!
I invested time (much more than 4h) in creating the app, creating tests, making sure it passes as many cases as possible.
After submitting it I was rejected because some old school C issues, probably some missing pointer checks.
Companies, writing the good old C is hard, compared to other languages! Pay for it! Also, take note, some companies PAY for home assignments !