Show HN: Every problem and solution in Beyond Cracking the Coding Interview
We just compiled every problem (and solution) in the book and made them available for free. There are ~230 problems in total. Some of them are classics like n-queens, but almost all are new and not found in the original CTCI.
You can read through the problems and solutions, or you work them with our AI Interviewer, which is also free. I'd recommend doing AI Interviewer before you read the solutions, but you can do it in whichever order you like. (When you first get into AI Interviewer, you can configure which topics you want problems on, and at what difficulty level, and you can add topics and change difficulty levels as you go.)
Here's the link: https://start.interviewing.io/beyond-ctci/all-problems/techn... (You'll have to create an account if you don't already have one, but there's nothing else you need to do to access all the things.)
The whole thing is broken.
I’m currently preparing for interviews myself, so having access to high-quality, free resources like this is incredibly helpful. The AI interviewer feature, in particular, looks like it will be very useful for me. Thanks again to the author for making these resources available!
A few of you have asked why we made these problems free. The answer is twofold, simple, and maybe even a bit underwhelming:
1) We want people to read the book (To wit, we've also made 9 chapters of the book free: http://bctci.co/free-chapters)
2) We want people to use interviewing.io
In my career, I've written a lot of stuff about hiring, and I've shared a lot of interview-related materials (e.g., full length interview replays). I hate paywalls for content, and you probably do too... and I have never regretted making it free. In my experience, putting good stuff out there is the best way to market to an eng audience.
Am I the only one that interviewed people with lengthy resumes full of programming experience and when I asked them to do a simple programming exercise they fell flat on their face? I've seen experience in C, gave them take home two hour exam and they couldn't even get anything to compile. What he meant was he took a class a few years back.
You see it in other domains with extensive Excel experience and the guy gets hired and never heard of a vlookup.
I think some of the stuff is overkill but you need to select for people that know how to program.
I for one am glad they exist because I don't have a CS degree but learned on my own. I lucked into this profession through an online leetcode style screener and your book helped me immensely,so thank you
You don't need Leetcode style tests to weed those out. Much simpler problems will do it.
The writing is on the wall for Leetcode-style interviewing. The signal-to-noise ratio is diminishing in the age of AI (cheating). These sorts of puzzle challenges might no longer play a meaningful role going forward.
What is hopefully dying is companies asking verbatim LeetCode questions and candidates having to memorize a bunch of questions. We wrote this book largely because we wanted to teach people how to think. I knowing how to think is only going to get more valuable.
It’s FAR easier for companies to stick with the interview process they’ve used for decades—just mandate in-person interviews again—than to reinvent the wheel with some new, unproven format. Sure, there’s a growing need to assess more than just DS&A in initial screenings, but let’s be honest: those interviews aren’t going anywhere.
The REAL reason to make these resources free? Because it’s not a competitive advantage to offer problems to practice. There are already tons of free problems online. The real value isn’t in giving people a place to do problems—that already exists. The value is in the book. If you already know enough to do well on problems without the book, then you shouldn't have to pay to practice it.
I bet the genuine answer to your question is that she knows it's a resource that could help tons of people (at a time when tons of people need that help) and paywalling it means that it won't serve that same purpose.
(Maybe I am just bitter because I have more than once bombed a leet-code interview myself)
I interview a lot of people and my go-to coding question is actually a pretty simple question that might be found in a 2-year coding course. What I am looking for is production ready code, good error handling, tidy design, and understandable code. All things that leet-coding specifically discourages.
1. Raw mental horsepower
2. The ability to just repeatedly do focused learning, aka just grinding
And sure, it probably does favor #2 these days - but that is a critically important skill. You can trade one for the other, but everybody has some amount of both, and these questions figure out, roughly, your computed aggregate score of these.
They have a very high false negative rate, but an exceptionally low false positive rate for a 60 minute interview, so it works very well in companies with large interview candidate pipelines.
The furthest I've ever seen it go in practice: binary search, BFS/DFS, hash tables. I've never seen any more obscure algorithmic trick than standard uses of these algorithms and data structures.
I'm not saying leetcode doesn't have more insane questions, but interviews tend to be straightforward.
Sure, some interviews are pretty hard and some algorithms/data structures are not as common on the job. But given a complex enough system, you'll run into lots of situations where having this foundation will pay off. I mean, it's just computer science.
That's the thing about software engineering. You can get a lot done without knowing the foundational stuff. But then you're just a blunt instrument. Everything looks like a nail to a hammer.
Honestly it's 30-45 minutes where you can establish whether the person can code, and whether they have the basic foundational knowledge to crack efficiency problems is pretty hard to beat.
Whilst there's probably diminishing returns on making the actual challenge more and more difficult, the general concept is a lot fairer than the majority of other interview types I've had thrown at me. ( Usually something they've solved internally, where they expect you to regurgitate the same answers without the same context )