Meta Developer interview questions

Had brief phone conversation with interviewer initially, who scheduled a technical interview with an engineer working at Facebook HQ. The second technical interview was fairly relaxed, I was asked to solve two problems using collabedit.com, firstly, finding all the anagrams in an array of strings, secondly, finding the number of ways a given score could be reached for a game with 3 different ways of scoring (e.g. 3, 5 and 10 points). After the phone interview I was offered an onsite interview in at Menlo Park (travel expenses paid for). The interview day involved 4 back to back interviews with different engineers. The questions varied in complexity and required answers to be given on a white board. Those I can remember was implementing combinations(n, k), printing a binary tree L-R, and implementing a comparator function to sort files based on a certain naming convention. I found it difficult to make any personal connections with my interviewers, they all seemed rushed and uninterested in striking up conversation - it was not an enjoyable experience. Indeed, my first interviewer was clearly more interested in what he was working on as he arrived ~20minutes late.