Sprout Social Senior Software Engineer - Platform interview questions

Applied on web and got email response within a 2 days to setup half hour phone call with recruiter. Next was one hour interview with hiring manager or senior engineer on Google Hangouts. Some live coding on Collabedit. Next a "Challenge Assignment" (see below) which have a week to complete. They make the coding challenge review completely blind, taking out all references to your name, so they can review it without bias. I failed this step. If you don't know this specific coding, beware of spending tons of hours on it for them to just reject it.