Meta Software Developer interview questions

Overall interview process was fantastic! Loved it though I did not get the offer. Sourcing Recruiter contacted me on Linkedin when I was not looking. After 6 month or so I contacted same recruiter. I got prompt response from this point till the end. I went through 1st technical round of interview onsite as I was local to their HQ. They prefer onsite though one can choose phone interview. For me onsite worked out well.Nearly 1-hour interview with one person. Two programming questions one on link list and other on BST. For each involved finding the solution (easy to optimal) and then write code optimal solution. I did this pretty well as I had prepared for data structures and algos. They immediately called me for full day onsite interview. Again I prepared lot on data structures, algorithms and related problem solving. And boom..that was my mistake. I forgot to focus on system side (locking, synchronization, deadlock) in detail. 5 interviewers, 45 min each. No on asked on data structures/algo. Two interviewers asked on locking related question, 1 design, 1 manager and last guy did combo of everything. Mostly I screwed up on locking related questions as I took many hint and long time... sigh.. Everyone was professional. Communication was prompt and fast!