I had chosen to go onsite for the facebook recruiting process, so I interviewed at the Menlo Park HQ office. For the first fifteen ish minutes their engineer asked me about my background, some interesting problems I had worked on on Android etc. Then he asked me Leetcode medium question based on trees. I'm the sort of person who likes to take the time to understand the problem better, talk about possible approaches and agree on a solution, but in this case the interviewer seemed like he just wanted a solution as quick as possible. I took about 30 minutes to code and to test the edge cases. The code was perfect, and I was figuring out edge cases along the way by testing but the interviewer just kept interrupting me - giving me hints and edge cases and I hated that. He then proceeded to ask me a second question - a variation of a leetcode medium question that can be solved in linear time by using a "trick". If you try to normally solve this problem the first time you're not going to solve it optimally or take some time to think about it (which is what happened to me). I told the interviewer the solution and I started to code, but could not finish the problem. Needless to say next day I got a reject. If you're going to do a phone interview at facebook this is what I have noticed (and feedback from friends who went through the same): 1) You need to finish Leetcode. There is no better way to say this but they want a monkey who can spit out code. They're really not interested in how you work your way through the problem or optimize it. 2) Don't waste time thinking about how to solve the problem. The interviewer will just scribble in their notebook if you do this and flag you for slow coding. Again - spit out leetcode. 3) You will either get 2 mediums or 1 easy - 1medium for a phone screen. 4) You are responsible for keeping track of time. The interviewer will not rush you but if you go over the 20 minute unofficial limit for leetcode mediums, bye bye. This is not a company that care about how intelligent you are but how fast you can spit out code.