Yandex interview questions

Constist of 4 interview levels - formal communication with theory and basics. Second two stages constist of sport-programming tasks requiring "hand-based thinking" with online button ckicks control. Very strange system of selection. Takning into account that yandex has no any significant innovation anywhere that does not ad much innovative growth.

I really liked everything . But it was difficult for me. They asked 3 questions about algorithms and asked to proof correctness of this algorithm plus time and space complexity