I interviewed for a C# based SWE role with 4yoe. I was reached out to by a recruiter on LinkedIn. I had 1 call with a recruiter, a 90 minute technical zoom call, and a 3 hour technical zoom call. With recruiter follow up calls after the technical rounds. They do all of the coding interviews on CodeSignal. Kind of weird instead of being there the whole time they let you read the message then leave the call for 30 minutes while you implement the solution then they come back and go over it and they always ask a bunch of follow ups about optimization and how you'd adapt the solution to different use cases. The first technical was a movie catalog search problem, they give you the objects and everything it starts as a list and you need to improve it through hash map indexing, some follow ups about caching this round was pretty easy. The second round was more difficult, split into 2 parts. Part 1 was a trie problem, pretty hard to do in 30 minutes unless you practiced it a lot have to implement building a trie and searching the trie. The interviewer tried to take over to help me but the parts he wrote didn't really work so no chance of recovery for me after that, I thought it was a bit ironic he couldn't even answer his own interview question. Failing this is definitely why I got rejected. Part 2 was more of a psuedocode design session with a different person they stayed on the call the whole time they wanted me to create and order book of asks and bids for a stock and we spent the whole time talking about different data structures for high speed search optimizing for different things like binary search trie min heap, hash maps to pointers that sort of thing a lot of Big O notation around each data structure. Out the 3 engineers I talked to only 1 was actually on the team I was interviewing for which made it hard to get good information since all of the teams are independent and dont talk to eachother. Also having to take 3 hours out of a work day is always super inconvenient.