Meta Software Engineer interview questions

Applied through a current employee referral and was contacted for a initial phone call in 2 weeks.
 Afterwards, was booked for a technical phone screen. Talked to a very nice engineer who had not been at Facebook for too long. During the interview I was asked two fairly standard coding challenges dealing with strings and arrays.
 Went for an onsite 2-3 weeks later. Overall, I think they could have scheduled it a little better. I was told to get there 15 minutes early which is normal and we ended up starting my interview early. (first two rounds were technical coding) We were allotted about 1.5 hr but we ended up finish a bit earlier. Afterwards, I sat in the room for about 30 minutes waiting for someone to get me for lunch. Around noontime, I was picked up for lunch by hiring manager who took me to the canteen to have lunch. 
 After lunch, I came back to the room to start my interviews again. 
 Phone screen easy or medium on leetcode Onsite tree, graph, merge segments… design news feed. prepared through leetcode, aonecode.