I have always seen LeetCode problems as effectively hazing rituals in a job interview setting. A high pressure interview situation simply won’t bring out peak problem-solving capabilities in many people. At best you get some superficial insight into someone’s problem solving methodology, but at worst you filter out otherwise excellent fits for not being able to solve an ultimately inconsequential problem under pressure.
LeetCode questions as interview questions are mostly theater. Most people who do well on these aren’t actually “solving them” on the fly from scratch. They just happen to have seen the exact same problem before and retake the steps they’ve memorized to get to the answer. Testing whether or not someone can regurgitate the solution they have memorized to a math problem doesn’t tell you much about how they will perform in a truly novel non-contrived constraint problem scenario, which is generally what most dev work entails.
Perhaps if you are working at Bespoke Algorithms ‘R Us, benchmarking this would have more value to your org, but for most dev roles at most companies it is hard to see it as more than a compliance exercise, or maybe even as a tool to weed out those with families that can’t devote the hours/day to LC memorization.
The thing is, all these arguments can apply to any test you do during an interview. It is always under pressure, and it will always be incomplete. You will never know for sure before you actually hire the candidate.
If the interview for a coding job doesn't involve actual coding, how do you know that the candidate can code? What you may get are people who are just really good at selling themselves. Maybe a good fit for the sales department, but not so much for the technical position you are hiring for.
LeetCode is not perfect, but no test is.
As for the "memorization" aspect. You can certainly memorize solutions. But you can't just memorize every character of every solution and regurgitate it perfectly. You will need to make some generalizations, just to fit everything into your brain, and as you type it back, you will probably misremember something, and have to fix the bug or bridge the gap. Those are useful, real life coding skills.
Do not let the perfect obstruct the useful.
A FizzBuzz coding test - which is also imperfect - will weed out those who cannot code, and without the false negatives from LeetCode.
Programming is far more than writing code. Do you test their documentation skill? Their ability to work with others? To fix someone else's code? To identify and resolve ambiguities in the spec? To estimate development time?
Is the additional time needed for a LeetCode test over a FizzBuzz test worth the time taken from evaluating these other factors?
I actually never did LeetCode interviews, but I did some competitive programming, same idea.
And it tests more useful skills than FizzBuzz. I wouldn't recommend hard questions, as they usually require techniques that are not very useful for most jobs and that you have to specifically train for (ex: dynamic programming). But for easy to medium questions, in my experience, the bottleneck is usually misunderstanding the problem, and simple bugs like typos, off-by-one, reversed conditions, etc...
Understanding of the problem relates the the ability to read a spec correctly, and the ability to identify and resolve ambiguities is related. And if you can fix your own bugs, it also helps when fixing others.
Of course, it doesn't test everything, particularly not teamwork (I mean, it is similar to competitive programming, the opposite of teamwork), but it was never meant to, other parts of the interview can do that.
As for documentation, I think writing skills are important and undervalued. I mean it in the traditional sense, like writing novels. We could have candidates write essays, but like LeetCode, people will complain. I will, because I suck at this, but I understand the value. By the way, I find that LLMs help a lot for this, language models, are, after all, really good at language, especially technical writing that is more formal than creative writing. Of course, the LLM require guidance, but once it gets the technical part right, I find the writing is pretty solid.
I was looking at the Meta interview guide and it says:
> Let us know if you’ve seen the problem previously
and also:
> In your tech screen, you’ll be asked to solve two problems in roughly 35 minutes. Practice coding solutions to medium and hard problems in less than 15 minutes each to help you be ready for the constraints during the interview.
The only way I could solve two problems in 35 minutes is if I've seen them before or it is a variation of a problem I've seen before.
> Let us know if you’ve seen the problem previously
Or just say “I’ve seen this one before” until they get to one you actually have seen before and ace it.
Leetcode is a joke. I’ve hired a dozen or so high quality candidates using a short 2-3 hour take-home. It shows us more than leetcode ever could. And sometimes people take it places I could have never imagined, these are people we move quickly on and they are the highest performers in the org.
people would usually ask for what the 'trick' is and you won't be able to give the correct answer if you lie like that
A lot of the kinds of questions you'd want to skip have no trick. Also, presumably, if the question is to be swapped then they will not demand a full answer before doing the swap.
I think it's stupid to try to judge if someone has seen the question before. The only time it's wrong to have seen the question before is if someone tipped you off to that specific company's questions. I think that most people are not good enough at writing reasonable questions to attempt it. For that matter they are not good at picking reasonable questions for an interview out of a collection of problems either. People often choose problems that are excessively difficult, ambiguous, or even impossible to answer.
You still need to be able to give a few sentence summary of the solution, trick or not and you will need to be able to give an answer that actually matches if you are going to say "ive seen this question before, [implying you know how to solve it]" while you actually have not and are lying.
It doesn't matter if it is 'stupid', or 'wrong', or whatever other cope you want to invent, people will do it and if your caught in a lie because you do not even know the answer to that, you've disqualified yourself immediately and potentially get blackballed as a liar.
If I've caught such an immediate lie as an interviewer, I'd be a bit relieved on some level because I now have a legit excuse to end the interview series early and go do something else and save my coworkers from doing interviews, because for most interviewers, they are chores.
This was basically my experience in college too. There was no time to understand something, and tests didn't test your understanding. If you tried to solve a proof for the first time you'd run out of time and fail. You just had to grind homework and book questions until you could shit them out in 5 minutes each.
Unfortunately, employers aren’t hiring people to “understand” anything either. They are hiring fungible human resources who can follow instructions and grid out solutions. It took me years to understand this and I don’t like it, but it’s how most of the industry works.
Growing up I was fed a false idealistic version of college by every college-educated teacher and adult, and it cost me $40000, so the betrayal in academia was felt much more strongly than work.
That's an odd complaint. The time to solve a proof for the first time is when you're doing your homework. The course work is supposed to make you practice until your brain can easily pick up the recurring patterns.
Sure, if the course is very poorly designed or the student is very unmotivated, they may end up just memorizing everything while somehow avoiding understanding anything. But in real life, when someone says "Oh I understand it, just give me thirty minutes to solve it" and others "shit them out" in 5 minutes, it's usually the shitters who are ready to advance to the next level.
> That's an odd complaint.
No it's not. I'll make it simpler. If you know the material really well but haven't memorized the problems, you will test poorly. If you memorize the problems and have no real understanding of the material, you will test well. This is obviously the opposite of what you want to test.
At a certain point companies prefer employees who can memorize lots of trivial information and perform at a high level while being constantly monitored for adequate performance. Leetcode pop quizzes are excellent tests for this within an hour: POSIWID.[0] Should you work at these companies? Is this kind of employee optimal for company performance at an any given company size? I don’t have these answers.
[0] https://en.wikipedia.org/wiki/The_purpose_of_a_system_is_wha...
My POSIWID guess is reducing market liquidity and dev pay by reducing competition for staff. These companies have been caught for it before. Even though I was pretty close in getting these processes reformed at my previous big tech company and nobody hinted at that.
At this point I think it's a self perpetuating system, like medical residency sleep deprivation or 'accrediation', which incidentally makes changing hospitals a 6 month BS process for any doctor.
A certain segment of engineers voraciously and autistically defend the leetcode interview since they were selected by it and probably like competitive coding and they are exhausting to deal with. The sane reformers eventually give up and leave them to their empire of dirt since nobody gets promoted for changing these things in big tech companies.
I don't try to add any pressure, but going on call will require some resilience from each team member.
As long as you don’t wake me at 3AM to rotate a red-black tree, or find the median of two sorted arrays we should be good
I must remember to ask how many times those problems happen in company's code base in next interview. Or whatever they ask. And if it is more than one, ask if they have libraries for it... You know good development practises and all.
Exactly this. As someone that’s served as an oncall engineer for years now, the skills you need to operate a cluster are completely different from the things leetcode tests for.
Yes pressure affects people differently. Under stress, my communication skills and creativity improves but my mathematical thinking and problem solving abilities decline (slow down).
Creativity gets in the way of leetcode... Leetcode requires focus; you need to recall only the most relevant techniques for the problem, if you're being too creative and see too many possible solutions and you try to identify the most optimal one, it will slow you down and you will run out of time.
I tend to do better if the problems are more difficult with more time given. I'm built for solving difficult problems without hard time constraints. I'm bad at solving easy problems within limited time slots.
A good senior developer should be able to go out to lunch and know if the candidate has the skills and the right cultural match by the end. There's no need for coding tests or whiteboarding problems. I've seen some of the best developers I've worked with in 40 years of coding get turned away by Google and Apple because of their terrible interview processes. The only thing better than going out to lunch is working with the person for a couple of weeks. Ideally this happens on a paid contract basis. Of course our culture makes it more challenging to switch jobs if you want to work together first, but really no other interview process has ever provided good data.
At big companies HR and legal will say you need a reproducible, auditable, objective and defined interview process or you open yourself to a whole host of lawsuits, and you will get lawsuits because there is blood to squeeze from that lawsuit cow.
Also at large scale you cannot trust the entire corpus of employees since your are well beyond dunbars number, so the process is there to prevent cheater and nepotism clusters forming where random employees hire their incompetent drinking buddies or cousins after a single "lunch".
That process works for small companies, and it's an advantage they should leverage, it does not work for the large ones.
IMO you need work sample tests as a minimum, which means a coding assignment. Some people are great bullshitters at lunch.
I did a lot of leetcode stuff this year. Dozens of interviews, no takers.
What got me a job was that I was a solo founder running a business and learning how to make the most of limited resources. Aka I was someone that gets things done and spends the least amount possible to get there. Use the resources you have and show you can create value.
Again, it all comes down to show don't tell.
Leetcode is valuable as a way to practice and maybe reaffirm skills. It's not useful for hiring in a direct way.
If you hire using LeetCode, you will surround yourself with people who enjoy blogging about LeetCode in their free time.
LeetCode was never about LeetCode, it was always a stand in for culture.
It's now a signal for baseline compliance. That's generally good for companies that require mostly operationalists.
The problem is that anyone can learn to leetcode. If you're interested in doing something new and not just warehousing CS lawyers, you're gonna have to ask better questions than that.
Leetcode is often one or two rounds. You also get tested for culture and design interviews. This is not ideal but hard to see how FAANGs are gonna do it. I guess FAANGs need operationalists though except for their research arms. Dynamodb works well. Your job is to make it work 0.01% better to save a few mill.
> The problem is that anyone can learn to leetcode. If you're interested in doing something new and not just warehousing CS lawyers, you're gonna have to ask better questions than that.
I think the problem is that everyone thinks they can ask better questions and almost none of those people are qualified to judge their interviewing competency or have data to back themselves up. Every company has its own special interview techniques that it's convinced will lead to the best possible outcomes when those only demonstrably lead to the current staffing. To question any of that means pointing fingers at pretty much everyone and that's a political non-starter.
Leetcode is just a proxy for an IQ test. That's it. If you can study up and do well on leetcode, then you're smart. People getting hung up on how realistic the questions are, or whether you ever need to implement X data structure are confused.
Fact is that no job can give a reasonable test for how it is to work there short of working there. There's team dynamics, developer / project fit, etc etc. All you can ever do is measure some proxies. Leetcode is just a much better proxy than the old "how many ping-pong balls fit in a school bus" questions.
I don’t know that people generally have a problem with testing their knowledge, I think most people that hate on Leetcode (including myself) just don’t like to code in front of strangers in a timed setting like that.
I’ve never been good at tests in school. I probably averaged Cs on tests through college. Projects though? Aced them every time and sometimes got pulled aside and told I was highly exceeding the projects of others in the class. I just do well when I can think alone, or when I can actually work toward a solution with a coworker.
I’ve made the companies I work for millions of dollars. But put me in front of a white board and ask me an algorithm question? You’d think I was fresh out of CS101.
Yeah. Call it stage fright or performance anxiety or whatever you want. It doesn't matter if you want me to write code for you, being around other people makes me anxious and I can't think properly. I'm less anxious now compared to when I started my career, but coding interviews are the worst.
So, you're in one of two situations if you're getting leetcoded vs. let in through the side door at a company (i.e. through your network: the red carpet)
1. You're a newgrad. You have no work history, but you do have a lot of time on your hands and a desire to prove yourself. Go study leetcode and prove how awesome you are.
2. You're a senior engineer who has a small network (not a dig, lots of great developers are introverted and have small networks, myself included). In this case, it sucks but... just practice leetcode. Don't worry, the fact that you're a good engineer means you'll pick it up quickly. It's not the same skill as professional software development, but there's a ton of skill transfer, and it might even be a little fun.
Time crunch, test anxiety etc, those can be overcome by practicing. A lot of times really smart people are averse to practicing since they never had to do it in school. But, I'm telling you, any smart dev can learn to leetcode well while being timed. It'll be fine
IQ test questions are explicitly designed to be things you haven't seen before, solved within minutes per problem. If you've seen them before then the validity of the test is usually invalidated.
Leetcode is effectively the opposite, because each one is usually a CS paper by itself, which by definition took a very hard problem a long time for a very smart person to create and test the solution.
You cannot practically invent the a leetcode solution from whole cloth if you treat it like an IQ test question should be done. It's a sport and you get good at sports via drills until it become muscle memory.
Again, the IQ being measured isn't "Are you able to invent A* search during the interview?" but rather "Can you memorize and apply these algorithms?".
Believe it or not, most humans on earth can study as long as they want for leetcode and still won't do well on them. If you can drill and study for them and your scores improve... bam: that's the IQ test.
Actually - “how many golf balls fit into a VW Beatle” is a better proxy.
Those are called Fermi questions.
I agree. One could say that just administering proper iq test would be better but that would be seen as insulting or whatever and also potentially illegal so people resort to elaborate challenges like lc
you can only administer most iq tests once, maybe twice if its been quite a while and you can rely on them not remembering the questions properly to get a practice effect
I wish they'd just give IQ tests then.. I do just fine in those (~140) but not a leet coder at all.
IQ tests are known to encode cultural biases. DEI troubles and possible lawsuits down that path!
> Leetcode is just a proxy for an IQ test.
What? No. You need to practice to be truly effective at Leetcode.
yeah but what if you are smart but don't want to spend time on pointless bullshit?
I have a couple great companies on my resume because I ground these leetcode questions, but now that I’ve been working and in industry for 14 years… I don’t have the time to do the grind unless I’m explicitly looking for a job. The DS&A skills are still there, I use them and I’m glad I have them, but when someone reaches out to me to join their startup out of the blue and then hits me with the leetcode hard question that I haven’t seen in 8 years… well I’ve not passed those interviews. Usually I don’t say “ok, I’ll study for 4 weeks before the rounds” so I go in cold.
I never give these type of questions in my interviews of senior/staff+, I build out topical problems for the space I’m actually hiring for, then simplify it down to the interesting bits. I give a ramp, a simple problem, a more complex tweak to the simple problem that needs an interesting data structure (maybe needs a heap or similar) and then another tweak that forces them to abandon that data structure and do something novel. You can also fail this and still get hired.
With junior engineers, I’m sorry but I need something that looks like leetcode so I know you put the work in, and I can’t ask the topical questions because they have no frame of reference. These questions are like the common denominator for someone with no real world skills. I need to see that you’re driven and self motivated enough to teach yourself this (probably useless, when is the last time you had to implement merge sort) skill.
I also don’t think there is a great alternative. I put an extraordinary amount of work into making my questions that aren’t Leetcode, when they leak I’m heartbroken. I don’t want to just let a fancy school be the decision point, so I need to find a fair way to test. Asking people to do 1-2 days work or pair program… it’s usually caused a lot of dropping out of the funnel. So I would love to hear alternatives that are working for others
Leetcode can work well for junior / new grad candidates if you help & hint them a bit. For example they probably forgot breadth-first search, but if you give a couple hints about queues and they show tremendous swiftness, then that can be a good sign they’ll learn very quickly on the job. Does not prevent false negatives but reduces the FN rate and gives them what they really want (learning experience).
If you are the type of person who writes a big brain log(n) solution instead of n solution when there is no real reason (compute wise) and the log(n) is a pain in the ass to maintain.
I hope I never see you in my team.
There is a lot to say about this. Due to technical limitations, the Leetcode site uses odd corner cases in their test suite to guide practitioners to specific, bespoke solutions. It's kind of insidious.
Yes! Just say give me o(log(n)) dollars! Ah now you care about n and k.
IMO the worst problem with leetcode challenges are the fact they are 100% in the training set of LLMs.
They solve them instantly, and making matters worse they are 100% valueless to a company.
What universe do we live in that hiring managers want staff that are 100% as skilled as an LLM but probably not as strong in areas that actually matter?
The reality everyone with a brain is going to cheat on these, they are typically pretty early in the interview process and it will hopefully get replaced with a real world test.
At my last job we just used example problems that we had seen in the past, usually REST API focused with just enough nuance to make engineers think through it and potentially refactor their code. Then you can ask them specifics of their thought process and get insight to their experience.
Coding assessments are definitely valuable in general. What isn't valuable are the class leetcode problems, where you have to use a heap, or DP, or some random useless data structure to solve a problem in O(n) instead of O(n log n) time. How about instead of asking a simple problem that has an obscure solution, ask a complicated problem with an obvious solution, but one that tests their software engineering skills. Make them ask clarifying questions about which of the many edge cases they are expected to handle, and verify which can be ignored. Add additional requirements that make refactoring necessary. Add constraints about the environment and ask how the candidate would handle that.
>However, I usually trust my intuition quite a lot, and before giving it up I decided to find some strong arguments in favor of Leetcode (LC) interviews, and here they are.
Sounds like confirmation bias to me..
I would rather hire someone who has evidence of working on prior projects than someone who can solve brain teasers. There are many people who excel at LeetCode but struggle to build even simple software.
It's 2024, you can find tons of people with project experience AND who are good at LC. It's really saturated right now and it's very difficult to stand out.
> People that never done LC problems probably don’t even know how to implement some data structures. So when they face a difficult problem they will probably just use a brute force approach.
You don't need leetcode for that. It's sufficient to talk about datastructures. In fact, that is a much better and actually reasonable thing to do in an in an interview.
> I also like these questions because you can ask them to any kind of software developer, from frontend to DevOps.
Only those that will apply at your place, which will exclude me if you require a leetcode interview. So, in fact, you will be biased by prefiltering candidates.
It's like when companies say "we only hire the top 1%" and I ask "the top 1% of all engineers or the top 1% of the engineers that chose to apply at your company?"
I think the article missed the biggest argument in favor leetcode style interviews - that they are quick and cheap to administer, and relatively unbiased/objective.
The reason big companies use these interview methods, is because they have to interview tens of thousands of candidates per year. None of the common alternative interview methods that get tossed around can scale to thousands of applicants.
my retort to this article is this simple question: if you can look things up in an encyclopedia, why are you forced to recite it?
if even low parameter LLM can solve most of these leetcode examples that cost nothing to run, why are we using it to discriminate applicants to measure "how badly do you want the $250k/year"
It's almost like the people hiring are optimizing for masochists and there lies the devil, you want hyper-rationality because they are the easiest people to manipulate and brainwash.
Highly sensitive and type B personality aren't going to sit around and let them trade their life to destroy or trap large number of the population with addictive algorithms or drone target selection.
Matter of fact IQ was invented specifically to filter out the most programmable minds, you wouldn't be able to run a country's intelligence agency without being able to brainwash people or a corporation. The promoters at the helms are usually the exact opposite of the producers, unwavering, unforgiving, uncompromising.
L1 cache is useful (or maybe good processor design is the better analogy...)
Being quick at the command line, using the right tools, can get around VS code quick, can solve the more trivial code problems quick (or quickly critique LLM output or a blog post). It adds up.
> These interviews can identify candidates with strong problem-solving skills and logical reasoning abilities.
I would disagree with this premise. Leetcode identifies people who have just finished cramming for Leetcode questions. You don't need logical reasoning abilities to solve Leetcode, just encyclopedic knowledge of algorithms and data structures
This article was kind of lazy. It’s a lot of conjecture, a couple anecdotal observations, and some rhetoric for good measure. Basically, the content was a let down from the title. On the other hand, I didn’t know Data Scientist candidates would also be tested with LeetCode questions.
There’s just so much guesswork with these as interview questions. The number of different problem spaces is non-trivial, and understanding the nature of the problem space for use in work is quite different from being able to work out a problem in 30 minutes in front of other people often in a code editor that is unfamiliar.
We lack an agreed upon, specific way to evaluate someone’s talent in 30-90 minutes. LC problems are not a terribly efficient way to fix this.
> People don’t like LC interviews because they are bad at them,
I enjoy that this assertion is made with essentially no attempt to justify it, it's just said matter-of-factly as if it's just obvious truth. Well, let me speak at least for myself: Absolutely not.
These are not strong or well structured counter arguments. The first argument, for instance, reads as premature optimization via hiring practices.
There are thousands, and I’m not exaggerating, literally thousands of leetcode problems.
A lot of them require you to make, what to me at least, is some non-obvious clever observation about the problem. Sure the problem is talking about a guy robbing houses, but if you stand on your head and squint just right you’ll realize this is actually a graph cycle detection problem and you should use Floyd’s algorithm to solve it.
Because there are thousands of these problems the amount of time it would take someone to become familiar with them is prohibitive. So you are at the mercy of the interviewer, have they picked a super clever one, are they going to be ok with removing duplicates from the answer by tossing stuff in a set or do they want you to pull some dynamic programming out of thin air.
It’s the part where you have to divine the trick under pressure that measures nothing of value. I’ve been a professional software engineer for 2 decades. I’ve had times when I’ve been trying to solve some very tricky problem and done research and thought thoughts and come up with pretty clever solutions, or at least I think they are clever. Not once have I had to do this under pressure in a 45 minute time box with someone looking over my shoulder.
That’s my objection to leetcode. Sure it’s great if a candidate can recognize that your riddle about topological map rain capture is actually just a restatement of Kolger’s postulate at first glance (a problem and postulate I’ve just made up because I’m not going to wade back into leetcode right now) but that’s an insane thing to optimize for.
The vast majority of the problems programmers solve are actually just mapping business domains into code. The most common problems that need solving is taking squishy, incomplete, and contradictory requirements from multiple stakeholders and figuring out what needs to get done. People in the real world are rarely rolling their own data structures, because the red black tree you slap together is going to be infinitely worse than the battle tested highly optimized one you can pull out of the standard library or off your package manager.
In my long career I’ve had a handful of occasions to actually build a data structure or solve a problem with some very clever algorithm. And in those cases you don’t really want people shooting from the hip anyways, you would want them to do research and see what prior art exists so they can discover something like Floyd’s algorithm for finding cycles in a unidirectional graph (ok this one is real).
It is not clear to me what exactly leetcode tests. My best guess would be your ability to take a disguised questions and convert it into a handful of problem shapes and solve those. But if you grade leetcode like the website does during an interview, expect to lose a lot of perfectly fine candidates along the way.
I feel like the author missed the most critical point: Leetcode style interviews are great at weeding out terrible coders (95% of applicants) early on in the hiring process, but don't carry an as strong signal for separating excellent candidates from the good ones.
Asking standard array/string manipulation/sorting etc questions in a 30min phone screen is very valuable to save your engineers 5hrs on a poor candidate. Conversely, throwing an NP hard leetcode hard at a senior dev with 20 years of experience and excellent culture fit with your organization in the 9th interview is basically meaningless.
Conversely, throwing an NP hard leetcode hard at a senior dev with 20 years of experience and excellent culture fit with your organization in the 9th interview is basically meaningless.
Worse than meaningless, it's a great way to toss away a diamond in the rough.
Leetcode problems skew towards competitive programming and grinders. They do absolutely nothing to show real-world programming skills which involve: 1) working within a large, existing codebase, 2) strong code documentation and commit message habits, 3) understanding of coding styles within the company culture so that you don't write in an unintelligible, bespoke style, and 4) communication skills and the ability to work within a team so that the candidate is not fighting strong headwinds.
Welcome to your leetcode interview in the age of ai: https://leetcodewizard.io/
Also I love these comments, thank you all for vindicating my disdain for this practice.
I'm so sick of LeetCode nonsense, I'm inspired to make a denylist of every company and blog and username that promotes it.
Here is an allowlist: https://github.com/poteto/hiring-without-whiteboards
They are good and I've had nothing but positive experiences through them.
In all the tech phone interviews that I've done in my life I have NEVER failed a LC/algorithm related interview. My secret is to try to engage genuinely with the problem. And even when I haven't been able to solve a problem I still would get passed to next round bcs I'd be on the right track.
I still don't know what ppl are complaining about. LC have a correct solution and a good interviewer will pass you if you are on a good track. They are also relatively easy to prepare for. Now compare to actual BS which is the requirement to have done work in a particular track that the company is hiring for.
Now that's total BS, I can't get 5 years in python in like 2 weeks before interview no matter how motivated I may be for the job.
None of the points made in this article were original or insightful. Disappointing for an unorthodox position.
Aren't there supposed AI tools out there for cheating on these standardized tests?
There are, but they are easy to detect
In my experience, I just need the aha hint and I'm usually good. When I looked them up later I was slapping my hand on my head. How do you detect that?
For real ??