Like many aspiring software devs, I've prepped for interviews using Leetcode and HackerRank. While there is no shortage of questions, I find that they don't address head-on what you should be studying.

Leetcode ranks based on difficulty, but it's a suboptimal metric when you just want to study for an upcoming interview. Studying for a particular company? That feature is behind a paywall. HackerRank's Cracking the Coding Interview Course comes close, but I think the questions are mostly too rudimentary.

Rather than organizing by topic or difficulty, I've organized these questions based on what I'd study before an interview. Level 1 concepts are so common that understanding the solution will often help address variants you'll see in an interview. On the other end Level 3 concepts may come up more rarely, but they're nice to have in your back pocket.

I still think there's a ton of value in the more verbose sources out there. But if you're lost this is a good place to start.

Also, If you're having trouble solving these, I highly recommend you look at my algorithm guide, which contains interactive code that can solve many of these questions.