YoE: ~5, currently at a unicorn
I'm not sure what level I was interviewing for since that wasn't made clear to me, but I think it was L4. L3 would be weird given my experience.

Leaving out question specifics due to NDA.

However, I will include a list of questions I studied pretty intensely for this interview. https://leetcode.com/list/xtlv750h

I am in the bay area but was interviewing for another position not in MTV. However, the interview was in MTV.

Phone Screen:
Tree question. I passed this one pretty easily.

Getting feedback for this was pretty scary since the recruiter emailed me back with a super vague message that sounded like it'd be a reject. I was asked how I thought in the phone screen (I thought okay). He said I passed and that I would be going onsite for an interview, but interviewer said I "coded slowly". I thought it was weird feedback since I completed the problem with time to spare.

Onsite:
5 rounds. I was told to expect a systems design and a behavioral. I got neither.

Round 1:
2 part sets question. Went perfect.

Round 2:
2 parts sets question (different than round 1). Went perfect.

Round 3:
Math question. Went well at first but then the interviewer put in a really weird twist that made my solution not work and I spent the rest of the time on the problem. I think this one didn't go well. The recruiter said he was really impressed how far I got but I think he was just trying to make me feel better.

Lunch:
Lunch. Actually the food wasn't that great by Bay Area standards. At least it was free. My lunch interviewer was kind of shy so it felt more like an exercise of me trying to get them to talk to me.

Round 4:
Bombed this one. backtracking problem that can be optimised by DP. Was told not to use DP, came up with two separate solutions and coded one up, but had a bunch of silly mistakes that needed to be pointed out. I think this is what made me fail.

Round 5:
Intervals problem. I think I did just poorly/okay for this one. My interviewer came in saying he had two questions and that he didn't know the solutions to them. I only managed to solve one and with a suboptimal runtime.

Obviously I'm disappointed. Before round 3 I thought I was basically good to get hired because I had aced two questions already and I had a systems design / behavioral left, which I felt super prepared for. I got the feedback that I needed to work on my recursion (which is what I used to round 4), and that I needed to focus more on figuring out edge cases.

My advice to future interviewees is similar to what the recruiter will tell you. There's basically a rubric for interviewers which is

1. You break down the problem and make sure you understood it correctly
2. You discuss your implementation before you come up with it
3. You actually code it.

I approached every problem with this rubric.

Google recruiters can be a bit slow and your application can get lost (this was definitely my experience). Make sure you give them a reminder every once in a while (once a week or so), if you think they've forgotten about you. For example, the fact that I was going on-site seemed to have gotten lost until I reminded my recruiter.

Finally, just a little rant here:

I'll probably try again, but it's been a disappointing year for me full of rejection. I'm currently employed but not that happy with living in the bay area anymore, so it's really depressing to have to essentially be forced to stay here due to not getting any offers. All I can really do is continue to study and hopefully get an offer somewhere soon.