I applied through an employee referral. The process took 3 months. I interviewed at X in Mar 2014
Interview
I was introduced by a former employee and had a very long interview process. I had an online coding interview which was pretty easy. After that I had one coding and one data science interview. Then came the on-site interview which was two back-to-back data science/coding interviews on Skype. The process took so long (about 2 months since the first contact) that they told me that there are no positions left in Data Science team but they introduced me to Data Visualization team. I had 3 interviews with Data Visualization teams.
In overall, while the interview process was frustrating, all the interviews that I had was great source of learning. So many interesting people are working on Twitter and it'd be nice to get a chance to work along them.
Interview questions [1]
Question 1
I cannot disclose any question but the coding questions were quite common questions. The data science questions however was very challenging and of course interesting. They talked about some of the active projects that they are doing and asked me how I would solve some of the issues that they are facing right now. While the questions are open-ended (they are still trying to solve them themselves), you should be able to come with a reasonable solution and justify your answer. For the data visualization team, common questions are like "Suppose you want to visualize this scenario, what method would you use and why?". There were also some questions on basic of computer graphics which I was not very familiar with, but answered them anyway.
The recruiter got in touch to set up a screening call. I was asked basic questions concerning my background and my motivation. Then we had a coding challenge with a question I later found on LeetCode under the Twitter section for the last 6 months.
Case study was interesting; interviewer was previously from uber so some similar interview questions, techniques do apply, overall a good engaging exercise. Nothing to complain about. Overall it is okay
Interview questions [1]
Question 1
explain probability distribution, how to track cohorts, a/b testing, case study on casual inference, working sample codes based on sample user behavioural usage dataset.
Python Coding of data science algorithm. Python library fundamental knowledge questions.
Data structure and algorithms coding.
System design of distributed compute systems.
A behavioral question round.
Followed by a hiring manager round.
