blog article

3 Concepts to Ace before You Apply to a Selective Coding Bootcamp

By Asher King Abramson
Last updated on February 10, 2016

coding-bootcamp-concepts-to know-app-academy

Getting into an elite coding bootcamp is hard. You take a bunch of coding tests and technical interviews and it’s easy to get stressed out during the process. Top coding schools are also extremely selective. App Academy (where I'm an instructor) has an acceptance rate of 3% - that’s lower than Harvard.

But we want you to get in! We admit every student that jumps over our bar. And we want you to have the legs to make the jump. So if you want to get into the most selective coding schools, here’s what you’ll need to know:

Tip #1. Get comfortable with nested loops

What's a nested loop? A nested loop is a loop inside of a loop. They’re crucial for solving interview problems that make you compare items inside an array. Here are a couple examples:

There's one "until" nested inside of another "until".


There's one "for" nested inside of another "for". The same thing in javascript:


Note: the code above doesn't solve a specific problem. It's just an example of nested loops. Any representation of real code, living or dead, is purely coincidental.

Think of a clock.  Every time the minute hand circles all the way around, the hour hand goes up by one.  Same idea.

Here are some example problems that you should be able to solve, without help, using nested loops in a coding bootcamp interview:

  1. It's Easter Sunday and it's showtime for the Easter Bunny. He has 100 baskets to fill. He goes through each basket and puts an egg in. Then he goes back to the beginning. He stops at every second basket and if the basket has an egg in it (all of them do, in this case), he takes the egg out. Otherwise he puts an egg in.  Then he goes back to the beginning. He stops at every third basket, taking an egg out if there's an egg or putting an egg in if there isn't.  He does this for every fourth basket, fifth basket, etc., all the way up to every hundredth basket. Once he's finished, which baskets have eggs in them?  Write the code to solve this question.
  2. Write bubble_sort to sort an array. Look at the animation on wikipedia and try to figure out the code on your own. You can ignore the jargon on the wikipedia page. Just look at the animation.

Tip #2. "Be" the computer.

If I'm walking through an algorithm I just wrote, I'll write out what the variables are on paper. For the code above, take a look: 


You should be able to look at code you wrote and walk through that code from beginning to end, knowing exactly what every variable is at every point in time.  If you're watching The Godfather and you pause an hour in, you should know the names of all the characters onscreen.

If you can write everything out for problems like Easter Bunny and Bubble Sort, you're golden.

When I say "be" the computer, you should be able to think through your program step-by-step and know what the variables are. "Being" the computer is not zen. Undercaffeinated Chevy Chase agrees:

Tip #3. Defend your time and trust the material we give you

If you have no experience and you're willing to put in two hours a day of study, it will take you anywhere from four weeks to three months to get up to speed. You have to be comfortable spending focused chunks of your time on the prep work. Schedule the early mornings or weeknights in your calendar right now.

As easy as it sounds, scheduling time is where most students fail. If you’re struggling with the material or you can’t devote the time on your own, find a tutor or look into other structured learning options.

At App Academy, we developed a 4 week, part-time program called Bootcamp Prep to help students overcome this hurdle. Through Bootcamp Prep, App Academy instructors will train you on web development fundamentals, provide interview prep, and one-on-one application assistance. More importantly, if you don’t get into a bootcamp after graduating, the course is free! You can find out more about the program here.

Bonus Advice

We put a lot of thought into the right materials to prep our students. Go through all the materials we recommend. If you want more specific advice:

  1. Finish the Codecademy track for your programming language.
  2. Read the introductory book your bootcamp recommends and type out the code as you go.
  3. Solve some of the easy and medium challenges on CoderByte. If you can’t solve a problem within 30 minutes, look at the solution. Don't get stuck.
  4. Get a tutor to help you through difficult concepts or sign up for a structured prep program like Bootcamp Prep.
  5. Optional: Some Javascript bootcamps will recommend that you're able to rewrite parts of the underscore library.

Want something more tangible? (Well, as tangible as code can be.) I wrote a worksheet for you. If you want some deliberate practice with nested loops, download this file. Try all the problems, then look at the solution.

TL;DR: Understand nested loops, put in the time and effort, and do the worksheet.


To learn more about App Academy Bootcamp Prep, check out the website here.

To learn more about App Academy, read reviews on Course Report.

If you have interesting questions or opportunities, email Asher at akingabramson [at symbol] Asher gets a high volume of emails, so he can't promise to respond to every one. He's rooting for you!

About The Author

Asher is a Software Engineer and Learning Architect at App Academy, the most selective coding bootcamp in San Francisco (3% admission rate). Asher is also the Founder of Learn20, a regular "learnathon" for autodidacts.

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