LinkedIn Sr. Software Engineer interview questions

Interview process is pretty standard with a phone round and onsite schedule for 5 interviews + lunch. 1. To start with phone round was average difficulty, questions from leetcode majorly. The only issue here, the interviewer trying to push his way of doing things on me, even though my way was better int time complexity and space complexity both. (Question: NestedList sum and basically reverse of that). I had to explain him in deep why is my code better and much more efficient, which as a Interviewer he should have caught much before me explaining him. 2.1 Onsite Hiring Manager Interview: Pretty straight forward and a lot of things we talked about including last projects and his last project and in the end he gave me a question he solved in 5 years to see my approach, overall really helpful interview. 2.2 Technical Communication: Again pretty straight forward interview take one of your best and one that you can clearly explain project and start talking about it, and answer any question they have. 2.3 Lunch: Pretty smooth. (Their cafeteria is much better than google and facebook quality wise!!) 2.4 Code Round1: Here all the negative started, one of the interviewer was a bit junior and the other senior and junior decided to lead the interview with one of the medium level question from Leetcode (Expression Operator). The problems: a] She didn't know how to solve the question she basically opened the LeetCode on her computer to keep it checked with my answer b] They don't want you to use your approach as they don't understand (they were super unprepared like Super!) c] Two interviewers not listening to my answers that I am giving to other one instead concentrating on their own questions instead of constructive its more like (You are Wrong!) kind of interview. d] They asked me to optimize the code which was optimized till the core (Basically expecting 4^n solution set but time complexity less than 4^n). They didn't understand this and kept pulling me till the end of the hour when one of them finally understood he was wrong and said that "This is most optimized one"; however the second lady didn't hear this and made a point that I didn't optimize it!!!! :/ (Stupid alert!!) 2.5 Design Interview: The lady was really helpful and wanted to understand my approach (Seemed pretty rear in Linkedin looking at other interview experiences) 2.6 Coding round 2: Both the engineers were super cool, one of hard level question I believe(Find k most closest nodes in BST, basically becomes hard when you improve time complexity) and the other one was finding square root of a number can be any number even decimals. I got the response from my recruiter in 3 days saying they rejected me, because "I Couldn't optimize the code in my first coding round" Duh!!! I sent my recruiter email with all the details and how unprepared the interviewers were and she replied saying nothing can be done now as the decision is already taken however they will make sure it doesn't happen again!! (Looking at the other interviews it doesn't look like they do anything with the feedback) In Summary: Great recruiter, very prompt and smooth process, but the actual interviews they tend to depend more on your luck (I don't like that!!). If the company improves the interviewers chances of getting right talent is a ton, and overall company really had healthy feeling. But again unprepared, lack of interest from interviewers killed my dream to join linkedin.