After sending my CV via email, I received a response within a few weeks to attend a written test. It consisted of 4-5 data structure and algorithm tasks, and 2 from math. The difficulty of the tasks was average to hard.

Afterwards, I was invited to an interview. I was interviewed by 3 different interviewers who mainly asked some other data structure questions. It seemed that the tasks on the interview were easier than on the test, but during my answers, they asked several related questions to describe time and space complexity and my solutions to some edge cases.

After the interview, I waited for around 2 months for a response, but since I got an offer, it didn't matter.

The most difficult question was probably constructing an OCR engine.

At the time, I pretty much just knew what OCR stands for, but with the guidance of an interviewer, I arrived at an answer.