I applied through other source. The process took 4 days. I interviewed at Instacart in Apr 2014
Interview
Was cold called and had a conversation with an engineer on the phone. He was kind enough to answer a lot of questions, and asked an open-ended yet very specific question about the shopping process they're trying to optimize. Despite the ambiguity of the problem it felt like he was looking for some particular answers he may have been familiar with. In the end he proposed to send over detailed descriptions of the problem and some actual data, and asked for the solution to be coded up and sent back.
Interview questions [1]
Question 1
The problem he asked to be solved is one of their most immediate business challenges, full-blown, not a coding test or even a restricted example at all. So it was odd they'd expect you to work on something for a week that an actual employee would spend several weeks refining. I thought it was to demonstrate coding and analytics skills, and provided a succint, well-commented solution, but didn't try to overdo it.
After sending it back apparently somebody else had to assess the code for them. Then what they said sounded like the solution was "only" doing as well as some other method they may have had, and that because of this they wouldn't move forward with the interview. Considering the strange process I'm not unhappy about this, but it's funny that (1) they would apparently benchmark you against something they gave you no information about; (2) they wouldn't say beforehand this would be their de facto decision process; (3) they would make a candidate work on one of the major challenges their business is hinging on. Draw your conclusions.
Faced a deep technical challenge during the interview, asked to design a personalization algorithm for product recommendations. I walked them through feature engineering and model choices, which stressed me out initially. Luckily, I realized the structure was almost identical to a problem I had explored on prachub.com while prepping. The interview progressed through a behavioral round where they focused on my previous experiences, and I ultimately received an offer, but decided to decline after careful consideration. Overall, it was intense but rewarding.
It was pretty straightforward. HR and then technicals. The technicals were a mix of statistics and math questions. Overall, it moved pretty quickly. My interviewer was quite late with no apology and in general not very friendly. I knew someone interviewing at the same time and they had a much better experience and recieved the same questions.
Interview questions [1]
Question 1
Suppose we wanted to launch 15-minute deliveries in a specific area where we already deliver. How would you statistically test the results?
