I had two interviews by Skype and one on-site.
The interviewers were pleasant and helpful.
Both Skype interviews took roughly 40 minutes. The on-site interview consisted of four parts and took around four hours.
There were some easy problems, like counting words in a string and reversing a linked list, and some questions about complexity analysis.
More advanced questions included printing the values of leaves of two trees in ascending order.
The following metrics were computed from 40 interview experiences for the Yandex Software Engineer role in Russia.
Yandex's interview process for their Software Engineer roles in Russia is fairly selective, failing a large portion of engineers who go through it.
Candidates reported having very good feelings for Yandex's Software Engineer interview process in Russia.