I was contacted by external recruiter. Then one phone screen with a recruiter from the company. Then coding test for 2 hours. Then another guy who is a software engineer contacted with me asked bunch of technical questions that are collected from internet. Nothing very original, probably all questions he asked were among top 50 interview questions. He was a nice guy. Then they invite me to onsite in Houston. First interview was with a manager. General questions about my background. He asked some factual questions. Some of them were really stupid. I tried to answer all questions and I think my interpretations were good. I sometimes express that what he asks is not very meaningful because of xyz reason, he accepted etc.. Then he asked a coding question which was not hard. I solved it in less than 7-8 minutes I guess. You write code on a laptop. He look at the code and find a test case which fails the program. I suggest two ways to fix it and I fix it. Then he starts discussing which was is more efficient. I said express my idea. It was related with letters. I wrote the code in Java. He asked me, how can I efficiently convert uppercase letter to a lowercase letter. I answered using Java way of thinking. This guy was very interested in to the low level programming. He talks about a tricky way to do it. Actually before he mentioned, I gave an answer which was very similar to his answer. He did not like it for some reason. Then we talk about test cases. I gave two different answers. I tried to point out that I would test boundary conditions as well as regular conditions. I suggested an automated way to test the program that I wrote. He liked the idea. Then he tried to confuse me with an another idea which was actually identical. He said that details are very important for the company etc.. He even go into machine code level details of the implementation. It was a weird interview. I don't really like the guy. He was obsessed with stupid tricks. Even though, your answers are close to the tricks that he amazed with, he does not like to recognize that you know what he has in his mind. Weird guy, a type of guy which is impossible to make him happy. Then another guy came, he asked some questions about my background previous work etc.. He seems like he was very interested in to what I did before. I recently finished my PhD, I talk about what I did for my dissertation etc.. He asked me to write a binary tree. I wrote it. Then he wanted me to test it by printing it. I wrote a method which had a slight problem, but I solved (he also give an idea while solving it). I tested the tree. Everything was working etc.. Two guys take me to lunch to a nice place. They told me that they won't give any feedback and I can ask any question that I want. I ask questions about the company and Houston. They seem like they were happy to work in Two Sigma and live in Houston. They tried to create an impression that very special people work in the company. They were nice guys. We returned to the company. The secretary came and said that they did not feel that I am a good match. Then I left from the company. It was a bit surprising because I wrote the code for two programming questions without any problem. Second interviewer behaved so nice. I answered most of first interviewers questions, I discussed a little bit and persist correctness of my answers. Maybe he did not like me because I was not submissive lol :) .