A little bit of backgroud. I have 15+ years experience in the industry. Learned a lot in the last 6 months, solved 350+ LC questions.

Recently interviewed twice with Facebook, for the following roles:

1. Software engineeer (SE)
2. Production engineer (PE)

The interviews weren't hard at all.

SE

Coding: Left most column with 1 in a binary matrix
I implemented brute-force, and then optimization using binary search (didn't complete due to lack of time). It did not move forward to onsite.
I believe that had to do with not completing in 45 min.

PE

Coding:

1. Goat latin
2. Dino speed

Systems: What is swap memory? What would you do incase a node consumes a lot of memory in production?

Both of them were easy. I even ran the questions in LC and also ran it on my machine. I was 100% sure this time, I would go to onsite interview.
The recruiter got back, "moving with other candidates".

I learned a lot from LC. It so much work especially the premium, when I find time, I challenge myself and learn more and more. It isn't easy to balance work/family and prepare for an interview. After doing well, the results are negative :(

What I don't get , is coding round about solving and explaining the solution on a white-board or something more?

PS: This is not the first FB interview, I've been to.