Google Foobar Interview Experience

Foobar is “said to be” Google’s secret hiring challenge, and it’s really exciting. It is an invite-only challenge, so “you have to be chosen” by Google.

There’s no specific word from Google, but it’s said that, based on your search history, i.e., your problem-solving related search keywords, their algorithm may find your searches interesting and send you the invite. 

Don’t find Foobar, let Foobar find you!

• Let’s talk about the thing we are actually interested in. It starts with a story where the villain (Commander Lambda) is trying to take over a bunny planet and has enslaved the bunnies. The task is to save the bunnies. You have infiltrated the villain’s ship and now have to solve a few problems to rescue the bunnies and escape. There are 5 levels in the challenge with increasing difficulty.
• In the first level, you’ll get ONE fairly easy question. It can be completed then and there within an hour (max) or so . When I took the challenge for the first time, I was given 2 days (48 hours) to complete the problem.
• The second level had questions related to the famous algorithms Breadth first search and Depth first search with a little bit of linear algebra. You get three days for each of the two questions. You get a referral link through which you can let a friend enter foobar!
• The third level had questions of number theory, dynamic programming, and even steady-state machines. Here you get three questions, you get seven days for each. It scared me at first, but it wasn’t that difficult if you are active in competitive programming.
• After the third level you get an option to share your contact details with google’s recruitment team
• Currently, I am on Level 4th and I have already solved one of the three problems 

Some tips:

1. Don’t Overthink: Overthinking can make you use algorithms that might be overkill. For one question I went on to implement Edmund’s Blossom algorithm while all I needed was a simple depth first search based bipartite matching. All the questions in foobar are mostly solvable in under 400 lines of code.
2. Don’t feel like it is the only way into Google
3. Refer to the internet when you don’t know
4. Try to learn the concepts and then start solving. This challenge will surely teach you a lot. You might hit a question that you have no idea about. The internet will be a friend, but don’t let it spoil you.
5. Also try to go for the challenge when you have ample of time to work on it only and try to learn at each step.

Foobar is more about learning and implementing, instead of knowing everything before!