I applied through an employee referral. The process took 2 weeks. I interviewed at X (San Francisco, CA) in Mar 2013
Interview
I was referred internally, and a recruiter got back to me within 24 hours. The first step was two autograded coding challenges on Codility, 1 hour total, which was pretty easy (question difficulty was equivalent to their demo test). Just be careful because the autograder can be very picky.
After that, I got a 45 minute phone screen and three "on-site" back-to-back 45 minute interviews through Skype. The interviews weren't too bad, but the difficulty of your questions really depends on your interviewer. I did fine on interviews #1 and #3, but completely flubbed up on interview #2.
After my last round of interviews on Wednesday afternoon, I received a rejection from Twitter Friday morning.
Good luck to anyone else trying at Twitter!
Interview questions [1]
Question 1
My interviews used in-place quicksort, binary search tree (in-order) traversals, binary search, and solid OOP class structure knowledge. By chance, all of my interview questions wanted me to do the questions in-place with only constant memory. No queues or stacks in my case.
Everything went fine, the first interview was an easy leetcode problem, the second was a medium dp leetcode problem. The process started on Nov 20 and ended on Jan 21. The recruiter was really nice and the interviewers the same
After the initial phone interview (this followed the standard resume review and coding assessment) I completed a series of three final interviews (one behavioral and two technical). All of these three final interviews were on the same day and over video.
Interview questions [1]
Question 1
Behavioral questions were standard (resume questions, experiences within a team, etc.)
Coding questions were inverse intervals and maximum of a sliding window
After applied online they emailed an online accessment with very easy questions (saying it's optional). Got all of them correct, but no reply since then. Not even a rejection letter.
Interview questions [1]
Question 1
Four fairly easy questions (all of which are easy questions on LeetCode)