During my in-person interview I was asked to write a few versions of a string-copy function, and we also walked through how to construct a garbage collector. The skills test is confidential, but prospective employees should be aware of a variety of topics from memory, to debugging, to AI concepts. Not all questions need to be answered in the allotted time, but having some knowledge in as many categories as possible and solid knowledge is a few should get you through depending on your level of entry.
