a/A, the bootcamp primarily represented on this sheet, is indeed very selective. The spreadsheet is not filtered though not all alums participated. a/A tends to accept people with STEM degrees from good schools or people with career experience that translates fairly well to software development. I went to a/A 3 years ago as a college dropout who played poker professionally for a number of years. I remember being intimidated going in when the intro emails started flying and everyone seemed to be an engineering graduate from an Ivy League school or similar.
As part of the pre-course prep and application process, candidates are going to cover a good bit of ground. They won't have studied algorithms proper, but they'll have mastery of loops, control flow, and many toy problems.
Once the program starts, they'll get exposed to some basic algorithms and design principles by building games like chess or computer controlled hangman guesser. From there they will be introduced to web programming, javascript, and the relevant frameworks the program focuses on.
Then it's pulling it all together to build a site, create a portfolio, and begin studying data structures and algorithms. The last 2-3 weeks of the course are dedicated to data structures, practice whiteboarding, and job applications. Not many people are passing the Google interviews at the end of the 12 weeks, but some do. What usually happens is that people that are set on working at the Googles or Facebooks spend another month or so studying their butts off with things like Cracking the Coding Interview until they're ready.
