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Show HN: Every problem and solution in Beyond Cracking the Coding Interview
Hey HN, I'm Aline, founder of interviewing.io and one of the authors of Beyond Cracking the Coding Interview (the official sequel to CTCI).
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/technical-topics 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.)
- bungled 1y agoAline and team are doing great work. Love to see this!
- dwightgunning 1y agoProud to have helped work on this. Happy to field any questions.
- squeegee_scream 1y agoWhy make the questions and AI interviewing free? This sounds too good to be true
- leeny 1y agoOP here. 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 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.
- dcsan 1y agoThis sounds like an amazing resource. What’s the rationale for making it all free?
- Peroni 1y agoAline is a bit of a Hacker News legend. She's been active here for longer than most people have been working and when you see how she's built her product, it's plainly obvious that she legitimately understands and sides with the HN community. 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.
- notyourwork 1y agoWhat does “side with the community” mean?
- diarrhea 1y ago> What’s the rationale for making it all free? 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.
- michael_mroczka 1y agoHot take from the author: This is a commonly repeated claim, but it’s probably not accurate. 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.
- constantcrying 1y ago[flagged]
- FirmwareBurner 1y agoNo other engineering discipline has such a low barrier to entry where everyone can self tech themselves at home almost everything people that go through the higher education pipeline can, and then extra on top due to how fast the industry evolves, where even having a degree might not make you qualified for a job today. In no other engineering discipline is all the tooling FOSS. So the PRO is that anyone can become a SW engineer, but the CON is that when anyone can become a SW engineer you're competing with soo many people on an even playing field that weeding out the wheat from the chaff is tricky and no company had the perfect solution because it doesn't exist. What other engineering profession things change so fast that tools from ~20 years ago (C, PHP, Perl, etc) are not useful on the job market anymore? What other engineering profession gets hundreds/thousands of applicants per open position? What other engineering profession has such a lack of standardization that every company works completely different, with different tools and different processes to ultimately do the same thing? In most other traditional engineering disciplines it's not just the university degree or credential that matters to getting in, but a lot of critical knowledge can only be gained from mentoring and learning at the job from graybeards of the industry, knowledge you'll never get if you try to teach yourself, even if technically all the relevant courses and information is freely available online. Not to mention that in a lot of engineering professions the tooling is specialized, non-FOSS and very $$$, so your only chance of touching it is at university or a company who will pay you to get certified in that tooling.
- constantcrying 1y agoHow many 100% self taught, no prior experience people are applying to these positions and are accepted for interviews? Obviously that number is extremely low especially given the last couple of years. Having a process which only exist for the 1% of least likely candidates is absurd. Even if you wanted to give these people w chance, obviously you don't need to subject the 99% of people to the same process. What is the point of asking a CS graduate with 5 years industry experience some brain teaser questions? There is literally no point, it tells you exactly zero about the candidate. Also, you can self teach everything in most engineering disciplines. What part of Electrical engineering or mechanical engineering requires a substantial financial investment or has things you could only learn in a university?
- quelup 1y agoThis is awesome. Just for awareness - I started going through the book a few days ago and there's a lot of other useful information outside of the LC style questions (e.g. what's actually important on a resume, how to realistically get your foot in the door with companies, etc.). Very data driven and comprehensive, so for me there's still a lot of value in the non LC parts of the book.
- lr0 1y ago[flagged]
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- tomhow 1y agoThat comment and yours both broke the guidelines [1], particularly the one that asks us not to "fulminate". It's fine and welcome here to critique anything, we're just trying to make HN something other than a ragefest, particularly about topics that people have been saying the same enraged things about for a long time. When the same things have been said about an issue for a long time, it's time to think about new ideas and new solutions to that issue. [1] https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
- bko 1y agoThank you for this. Some people are critical of coding tests but I do this there is a point: namely to weed out people who can't code. 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
- stmw 1y agoYou are not the only one. I've interviewed probably 1000's of engineers and it is striking how often one runs into candidates that can't code... or ones that operate at a level far below what you would expect.
- bornfreddy 1y agoMeh. There is a world of difference between 1337code problems and anything one encounters in the real life. Judging someone by that 1h slot on a domain they haven't worked on for decades doesn't paint the right picture. It does tell a lot about the priorities of the company though, so there's that.
- stmw 1y agoI think it paints part of a picture - obviously you shouldn't hire just based on top score in an algorithmic interview. But if I interview someone for a JOB WRITING CODE with decades of experience and they refuse to write code and can't explain the difference between a linked list and an array, that's a good argument for reconsidering hiring them...
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- AndrewStephens 1y agoCracking the Code Interview is a great book and excellent for practice and brushing up. But I have found leet-code questions terrible for actually interviewing candidates. A lot of them boil down to whether the candidate knows the specific trick or can regurgitate the memorized solution. (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.
- paxys 1y agoPeople keep saying this, but no one ever shares any meaningful data to make their case. Tech companies have been using Leetcode-style interviews to hire programmers for decades, and have grown in value from nothing to trillions of dollars in that time. The industry as a whole is worth tens of trillions, and the software these fake Leetcode programmers have built has eaten the world. Large companies have all spent billions on recruiting and internal processes and have come to the same conclusion - coding interviews work, and are very effective. Why should they stop? Vibes? Online comments?
- dimgl 1y agoI used to agree with the anti-Leetcode sentiment like the OP, but changed my tune fairly quickly once I started doing actual production-grade software engineering that goes beyond just simple CRUD and realized the things that Leetcode tests are applicable everywhere. It just kinda clicked one day for me and I started passing Leetcode assessments. 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.
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- slackware_linux 1y agoIncredible value here, thanks for sharing Aline. The book itself is a wonderful resource, not just for the technical chapters but the rest on resumes and reaching out etc. Even the technical portion provides the framework (boundary thinking, triggers, etc.) which is above and beyond basically any other resource online or in print. The AI interviewer is also super useful and the 'book' section of the site is very well put together. 10/10.
- QuadmasterXLII 1y agoHot take: these interesting, contained problems that you really can solve on your own are a finite resource, and every time you read the solution to one you permanently deplete that resource for yourself.
- stuartjohnson12 1y agoHotter take: manipulating intelligence signals is more effective for achieving things than doing things to improve intelligence.
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- commandlinefan 1y agoYou can hedge against that by trying your best to solve the problem once before reading the solution.
- tanchaowen84 1y agoTo be honest, I’ve done quite a bit of LeetCode, and while it’s great for practicing algorithms and problem-solving, I’ve found that I rarely use these “fancy” algorithms in my actual work. Most of the time, what really matters is breaking down requirements into clear logic, writing maintainable and collaborative code, and communicating well with the team. These skills are hard to assess through algorithm-focused interviews alone. I really hope interviews can place more emphasis on practical engineering skills and real-world scenarios, which would be more valuable for both companies and candidates. 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!
- IshKebab 1y agoI think it really depends on the job. In most jobs I've had the algorithms rarely get more complicated than just avoiding accidental O(N^2). The sort of thing where juniors would do a linear search. But I did have one job working on an AI graph compiler which used fancy algorithms all over the place. In practice though I found the space between "use the standard library" and "it's NP-complete; use heuristics" where the answer is "you can use this neat dynamic programming trick" is basically nonexistent.
- jwmoz 1y ago'Principal' developer at my last place spent 100 consecutive days grinding leetcode. Shortly after had an interview where they made him do a leetcode test live and he failed it. The whole thing is broken.
- Spivak 1y agoIt's a whole separate skill to be able to code with an audience, let alone an audience who is judging you. I could forgive a non-technical interviewer not knowing this but surely someone who is a dev themselves understands the very real performance anxiety. It's bonkers why we do this to people— the best I've seen is the in person talks about their experience, architecture, problems they've encountered and how they solved them and then either code samples from their public code if they have some or a short take-home assignment if they don't. They could cheat on the take-home but it isn't meant to be difficult and you hopefully figured out at the in-person that they're someone who wouldn't need to bother cheating.
- jwmoz 1y agoIt's almost impossible for me to do any serious work or problem solving in an interview situation due to anxiety and stress-my mind simple does not work the same way as it does when relaxed and in flow.
- daseiner1 1y agoA good analogy I’ve been told is the NFL combine. Vertical jump, straight-line speed, and bench press performances are probably moderately correlated with on-field performance, but the best test of playing the game is playing the game. I more understand the emphasis on leetcode problems for juniors but a timed session without an observer (perhaps with browser tracking) to solve those problems makes a lot more sense than bringing in the anxiety of the observer, as you’ve noted. It sucks having to spend mental energy wondering how your problem-solving looks to whoever’s watching and seems actively detrimental to assessing talent for an IC role.
- w0mbat 1y agoI can't code with somebody looking over my shoulder. I need to relax and think about the task. They expect me to code while being judged by one or more strangers, against the clock, with high stakes involved. If that was the actual job I would not apply for it.
- davidpfarrell 1y agoHow did your site know my first/last name when I gave my email address to create an account and clicked the confirmation link you sent?
- leeny 1y agoWe use Clearbit for enrichment: https://clearbit.com/ https://clearbit.com/ That said, all interviews on interviewing.io are anonymous unless you and your interviewer both explicitly opt in to unmask.
- devnull3 1y agoI wonder which other professions or trade ask people to perform infront of them in a simulated env as a filter criteria. Actors for sure with auditions and maybe maybe chefs, male pornstars.
- lapcat 1y agoOnly male?
- devnull3 1y agoMales are under pressure to "sustain" it for 10-15 min atleast (with many people watching). For females, no such thing.
- throwanem 1y ago[flagged]
- williamdclt 1y agoThey didn't say anything about acting? They said men have to "sustain" - ie hold an erection without ejaculating.
- throwanem 1y agoRight. Acting. It isn't more difficult for men because their part is, uh, hydraulically obvious. More to the point, it isn't less hard work for women. I get why guys assume it would be, though. Good grief, I bet you probably think you've never seen anyone fake an orgasm outside a porno, too...
- mathgradthrow 1y agogender roles, and dare I say even sex roles, are actually noticeably different in sex.
- avinassh 1y agoI would like to give a try, but I am getting this for India: My name is Aline, and I'm the founder of interviewing.io. Thanks so much for your interest. It looks like you’re not in a country where we’re open for business yet, so we can’t create your account, but we’ll add you to our waitlist.
- leeny 1y agoOdd, that shouldn't be happening. Can you please email support@ and say you're trying to access the book materials, and we'll investigate
- joshdavham 1y agoI think the reason leetcode problems are still popular is because they test whether a candidate is willing to work hard (‘grind’) on problems that don’t even matter. A lot like what actually goes on at a FAANG company.
- hakkotsu 1y agoHard disagree. At FAANG companies, working on problems that "don't matter" is exactly how you get a "Meets Some" or worse at your next perf review. These companies are obsessed with measurable impact - you need to show clear business value, user metrics, or revenue impact. Spend 6 months grinding on irrelevant work and you'll be on a PIP in a blink of an eye
- slipnslider 1y ago>working on problems that "don't matter" Usually low level engineers don't have a say on what projects they get to work. They show impact by completing whatever projects were handed to them and hope/pray those projects take off and become visible to upper management and/or tied directly to revenue. The grind aspect is real though. 99% of FAANG engineers aren't building the next google maps or LLM, they are doing Enterprise CRUD + ELT + jira tickets. Companies like Meta and Amazon have enormous workloads and thus a grinder is preferable. After a few years of experience, CRUD and ETL can be done while sleepwalking so the only missing component is someone willing to grind, e.g. someone who will spend 100 consecutive days doing leetcode
- OnionBlender 1y agoI wish I could just submit my solution and be told if it passes instead of dealing with the AI Interviewer. A lot of problems don't have a leetcode equivalent.
- leeny 1y agoYou can try to short-circuit the AI Interviewer by just entering your solution into the IDE. OR you can ask to end the interview, and then you'll get a link to the solution. We built it this way on purpose, though... the intent is to mimic an interview and gently force you to talk through your thought process, not to have yet another LeetCode clone.
- neilv 1y agoLong ago, some dotcom, founded by students who'd never worked, used their own idea at the time about what software development is about (i.e., Stanford first-year CS problem sets). And since that company had a lot of money (for different reasons), a lot of wannabe companies tried to mimic whatever they did. Today, CS student's idea of an industry interview has turned into an extortion racket cottage industry, with people not only selling ritual prep books, but now also selling mock interview rituals with techbros who got into the best-paying companies. Youse has a lovely career potential; its would be a shame if somethings was ta happen to your job interview. What more does it take to realize this is very time-consuming and expensive theatre, and terrible metric for hiring good software engineers. And if you're an employer who doesn't care that students spend many hundreds of hours rehearsing for the interview theatre, to the exclusion of getting more experience building things, and that your interviews aren't actually selecting for software engineer aptitude, what happens when the hire takes that same misaligned hoops-jumping mindset to their work.
- hintymad 1y agoLeetCode-style interviews used to be an aptitude test, kinda like the weeder courses in college. Now that most people cram for them, they've lost their original purpose.