"Write a function that counts the number of vowels in a string"
Candidates are allowed to run it multiple times and just have to produce a correct result within 10 minutes. It's not a trick question -- the test case in place makes sure you pay attention to case.
Success rate for mid to senior devs? Only 60%.
Took me less than 10 seconds to come up with an approach that would work oh just though of a more efficient one but that would use a regex :-)
"Write a function that reverses the words in a (string) sentence"
i.e. (x) => x.split(' ').reverse().join(' ');
The fastest way to reverse a string is in JS is:
function reverse(s) {
var o = [];
for (var i = 0, len = s.length; i <= len; i++)
o.push(s.charAt(len - i));
return o.join('');
} return inputString.Count( "eaoiuAIEOU".Contains );
static Regex VowelMatcher = new Regex( "[aeiou]",
RegexOptions.Compiled | RegexOptions.IgnoreCase );
...
return VowelMatcher.Matches( inputString ).Count;
return 2; // number of vowels in "a string" def vc(s):
return len([c for c in s if c in ['a','e','i','o','u']])Our standard fizzbuzz question was something like: print the multiplication table. This is a loop inside a loop. I think every programmer should be able to do this given 10-20 minutes. Around 30%-40% couldn't. Like literally, didn't know how to do this in languages they supposedly work in. I'm sorry, I make lots of allowances for stress, I calm candidates, I tell them syntax doesn't matter, do it in pseoudo-code for all I care. But if after 10 minutes you can't print a multiplication table on the screen, I'm going to pass.
I've run into this issue in different specific ways earlier in my career and no matter what I'd say about skill level / lack of knowing required technologies / being willing to take lower pay in order to justify aiming for another role it didn't matter in the face of the possibility that the recruiter could obtain a larger % for themselves off of that senior / higher-than-in-my-range job's salary.
Maybe this isn't as applicable for senior dev role applicants as it is for some lower level dev roles but at the point an applicant is actually physically there in front of the interviewers I'm sure one of the last things they are going to want to admit is that they wished they were interviewing for a lower paying / easier job even if it's 110% in the favor of both parties.
I've tried working with them before, have gone on job interviews through them, and then generally found that the jobs that hire through recruiters pay peanuts, and I end up finding a permanent job paying much more and taking that instead. I think if a company only works through 3rd-party recruiters, that means the company has no idea how to hire people, and doesn't want to pay much either (because they're paying the recruiter a huge commission).
Not to mention most of the one's I worked with early in their career not only had no idea about any of the technologies they were checking to see if I was fluent in but they also acted like they DID know everything about programming and beyond that they tried to flaunt this fact and treat me like I was trying to overstate my skills to sneak my way into a job out of my pay range.
Such a frustrating ecosystem in order to find a career job.
In ten years I can count on 1 hand how many times I've gotten a reply from a non-recruiter job I applied for (applied on my own without a staffing agency submitting / representing me).
It's really crazy how that works.
Another thing I dealt with was people who hired me saying (TO MY FACE):
In this situation I'm making $35.00/hr as a Regular Developer (non-junior / non-senior dev, just a middle of the road contract developer):
CEO of company in front of everyone: "scoggs we are paying way more for you than we are for our senior developers so we are expecting top notch work from you."
Me (used to it by now, unfazed but I hate this situation): "Sir with all respect I'm only getting less than 1/2 of what you pay my staffing agency for my contract/"
CEO: "well they don't really do anything / didn't really do anything but introduce us and get you a phone and in person interview with us."
Me: "But you guys didn't have to pull programmers, HR, and design / copy writing people off of their normal work to create interview materal, submit interview material, review resumes, vet candidates, plan phone interviews and schedule them, set aside time for phone interviews, review phone interview candidates among 'hiring team', review candidates references, plan in person interviews and schedule them, execute in person interviews and have meetings with 'hiring team' to pick who to hire', make offers to people you want to hire, or hire them. All you had to do was tell the staffing agency what skills your were looking for and what kind of company you were. I'm not an employee of your company. I don't have insurance, I don't get paid for sick days, I don't get paid for holidays, and I have no job security."
Of course I didn't say all of this, I said something along the lines of "They take care of the majority of the process" but in my head I feel like I'm always having to live up to the expectations of the people paying the total bill. The same way they think the staffing agency doesn't do any real work and isn't worth the cost / price of doing business -- most of these people feel the same way about developers. They don't understand what we do, they just expect us to solve anything and everything to do with computers / programming / technology and this is ALWAYS the way it is regardless if the final product / project outcome is directly tied to the company suddenly turning a profit based on the success of this project / programming endeavor.
These companies want to underpay contract developers, pile stress on their shoulders, guilt them for the situation they have little to no control over, and then stick them with the majority of the blame if things don't go 200% well (because they are expecting work that's 2x as good as the amount of money I'm being paid).
I've found it impossible to truly and personally (mentally) live up to the majority of expectations laid upon my shoulders by non-technical CEO's / Presidents / Bosses of companies I've worked for.
This is the majority of what I deal with right outside of NYC in Northern New Jersey. There is the rare company that truly respects the programmers they hire (usually companies where programmers have become CEOs / Presidents / people in powerful positions within the company who wield influence).
I love the money I make in this market but I truly hate the way everything makes me feel even when the situation is like this yet I am able to deliver above and beyond expectations. I hate working for people and in situations where it feels like I'm being told I'm robbing the company when meanwhile the recruiter is robbing us both yet they have us pitted against one another -- and beyond that the staffing agency has a 2 year lock on me being able to accept a job from that company without them "buying out" my contract.
The cost of buying out a contract? A university wanted to do that once early in my career (I wish I was still working there frankly, 10 years later), but the staffing agency wanted 2x the amount the university was paying the staffing agency! I was making $60,000/yr at that point so on top of the University paying me somewhere in the realm of $60,000/yr they would have also had to pay the staffing agency ~$240,000 just for the right to hire me. That means they would have had to shell out $300,000 total including my salary and the buyout.
Nothing about that seems right and / or legal. Under no circumstances would I ever be worth that much to the staffing agency and honestly with the amount of work they actually do I feel like it's damn near criminal.
No State University that pays employees with citizen's tax money is ever going to be able to justify spending that type of money on 1 employee. It's just a fantasy of epic proportions.
Anyway, you make it sound like you can't get a job there without a recruiter. There's still plenty of companies hiring directly, I even interviewed at a few when I was there such as Alcatel at Bell Labs and some wifi company in Manhattan. My current gig is with a large company (in the DC area) that hired me directly. Stop wasting time with recruiters and just look for companies that do their own recruiting; there's no shortage out there that I've seen. I've had 8 jobs now that were not contracts and not through recruiters: 3 large corporations, 3 small companies, 1 mid-size, and one a state university research division. Am I apparently special that I'm able to find these jobs?
Personally, my first-line screen is a short answer (3-5 sentences) to a programming-related question. [1] For me, about 90% of applicants who pass that can also code. I like that better than a resume screen, as plenty of people who haven't officially been programmers are decent coders.
[1] Examples here under the "Join Us" section. https://web.archive.org/web/20151005181908/http://www.codefo...
Honestly, that's way too trivial to call "can code". I usually ask something less trivial, yet still extremely easy like "a function to check if a string is a palindrome" (I explain what a palindrome is) or "check if a substring exists in a given string".
You wouldn't believe how many people "with 10 years experience" just lose all motor function in their hands and mouth, even without any time pressure.
Coding in the large is project management and could be tested by a take home, but I'd rather tease it out by asking in person questions about organization, prioritization, and technology choice.
Throughout my career, I've been in professional situations where I was under a lot of pressure: Having to explain failures to executives, near-impossibly tight deadlines, production outages. At least I haven't had to testify in front of Congress yet. Absolutely NOTHING I've encountered in my professional day-to-day has the extreme level of pressure of a typical silicon valley job interview.
Because if I hire that person, they'll be in charge of critical production systems and will face much harder problems in much more stressful situations and if they can't handle the palindrome question, I have very little confidence they can handle the actual job.
Not claiming to be that hero, but I have personally had those moments where I came out of the interview, and as the disorienting fog of pressure lifted during my drive home I said to myself, "WTF happened to my brain in there? I know that stuff cold!"
EDIT: I think I read this one from a commenter here, but it's so true: We're interviewing people to be music composers, but judging them by their ability to be performance artists.
(i.e. bring out groovy, using bash, etc)
Is it reasonable to ask things like that? Maybe, maybe not.
But as stressful as an interview is, it's still a basic problem (I can English describe it to you in 30 seconds...coding (in C/C++) would take me another 5-8 minutes (and, probably, be pretty damn inefficient ... but it's still a simple problem)
Checking substring in a string is a 1 liner in languages like python.
I was at a final interview with FAANG. One question asked was to load a csv. I used pandas, it's a 1 liner. You could see the wretched face of the interviewer since he was expecting a
with open() as f: do_some_shit
and kept pushing me to write this on the board. I looked at him and said "Why? Why write your own method in a vanilla language? Give me a good reason."
That's like answering "how often do you need math?" to the question "what is 2+3?". It is an utterly, completely, stunningly trivial question that even a CS101 student on their first semester should be able to answer.
> used pandas, it's a 1 liner. You could see the wretched face of the interviewer since he was expecting a with open() as f: do_some_shit
I would be perfectly fine with the pandas answer, but my point is "csv parsing" wouldn't be my first question, I'd start with something much easier and if you managed that, I'd gladly accept pandas as a valid and then asked you to elaborate further (what does this pandas function do, how would you implement it yourself etc).
What are the downsides to using pandas? Is that worth brining in that large of a library for a matter like that.
They can't ask you a complicated problem, because they don't have the time (nor do you) to solve a real problem that requires coding.
You are totally missing the point of what they are trying to ask you if you insist on using pandas for parsing CSV. Understanding the point of what you are being asked to do is critical to being a professional software developer.
I’ll take someone who gives an idiomatic answer over someone who reinvents the wheel anyday. Who is likely to be more productive on the job?
They can definitely ask a complicated problem. On-sites are 4 hours long these days.
The ability to understand the underlying need behind a request is important to being a good employee. If a candidate fails completely to understand the purpose of a question during an interview, and in fact continues to argue against you as you explain it, they aren't a good candidate at all.
I agree with everything you've said, but that still makes it a bad and equally obtuse question. If they don't actually need a CSV parser, they don't need to know that you can parse CSVs, either (if you can - which is the other point - you might be a pretty good programmer if you can quickly parse a CSV, but there are tons of excellent programmers who can't).
And that was when I found out parsing something that should be as stupid simple as CSV file can actually be pretty complicated.
I understood the "purpose" of the question and I self-selected myself out of a role I would've been bored, micromanaged at, and probably not challenged at.
Overgeneralized at best, LOLworthy at worst. Does this include palindrome questions for Ruby that require the use of linked lists? Because I had that from a CTO of a couple-hundred person company not two months ago.
I think to some degree, a suspension of disbelief is reasonable for an interview, and it's not worthwhile to get tunnel vision on a particular problem asked. It's ok to point out that something is trivial with a particular widely used library or whatever, but if it is asked to implement something via first principles or whatever, it is a perfectly reasonable expectation to just do it for interview purposes as a simple mental exercise.
There's a few things going on here. First, there's a frustration from the interviewer who is obviously looking for the cookie-cutter answer to move things along. Second, there's a culture misalignment because they are looking for cookie cutters to do the job while I am not that. Third, they, along with OP, are obviously not a palindrome company nor a load-everything-to-lists company yet this is what they're testing. So again, culture misalignment.
At the end of the day, you are right, I self-selected myself out because I would not be happy at a place like such who are looking for cookie-cutter employees.
That you couldn't yield on such a trivial, manufactured matter would make me wonder how you respond in a team environment on real matters in the face of adversity.
One of my go-to questions is "sort this array", and if the candidate types `Arrays.sort(input)` they get bonus points, because it shows they have useful knowledge of the language they'll be writing in.
> I took my sunglasses off, looked him dead in the eye,
> and said "Why? Why write your own method in
> a vanilla language? Give me a good reason."
It's a synthetic interview question. Why does it suddenly need to be a production-ready CSV parser?
We don't have enough information to say whether these are bad interview questions, and it's really not the point.
Maybe the interviewer just wanted to see if you'd use good fd hygiene (`with open('file.txt') as f:`) and that you can stub out some toy parser code and speak of it intelligently. And that you wouldn't throw a fit when asked to write some code that a library like `npm install fizzbuzz` can already solve.
Creating a dependency to a library is not benign. Even if the library is easily available and mature doesn't mean that everyone has it, or that it will never change. Remember how "leftpad" broke npm?
Having that smug attitude towards the recruiter, assuming he is an experienced developers himself, should rise a red flag. Yes, sometimes projects have constraints (like "no pandas") that may seem stupid, and sometimes they are. But it is first important to understand the context.
So instead of asking "give me a good reason?" to the recruiter, give the reasons yourself. Invent a scenario where you actually need to rewrite that csv parser, bonus points if it is related to the company's business, and finally, write the damn code the recruiter wants you to write.
In my case about a decade ago, I became obstinate when given one of those silly math-trivia-puzzle problems like how many ping pong balls will fill an elevator or how long is a string. This was for a relatively senior track FAANG interview, where my background at the time was in HPC, distributed systems, and provisioning systems that were precursors to today's IaaS bread and butter. In my case, the interviewer was adamant that I derive some figures that depended on basic geometry and knowing the diameter of the earth and ratios of landmass to ocean surface. But, he wanted me to first SWAG these figures, after I told him I wasn't a geospatial geek and didn't memorize such facts.
I decided to be difficult. If I were somehow faced with such a task, I would first consult reference materials and even see if I could find the actual answer he wanted, since it sounded only one step removed from what you could find in the CIA World Fact Book or similar. Only if that failed, would I dig up source facts and try to derive an answer. I would focus on getting the answer, not on entertaining myself with a Martin Gardner puzzle at my employer's expense and risk. I would never have to make seat of the pants estimates and act on them rather than doing due diligence. I'd either have done homework, or if there was really no time (like some system availability crisis, if we pretend I was an ops person), I'd choose a pre-planned contingency action to make time.
They didn't go forward with an offer, and I felt a bit of relief at that.
I asked "Do you want me to do the simple thing, and use a library, or write code to do this?"
They preferred the latter. So I did.
As happy as it might make you to be snarky for the often silly questions you are asked, people are, if they are smart about it, looking to see your thought processes.
I recently got a question that I didn't know how to answer, so I started thinking through it aloud. I think they liked it, because they engaged with me during the process. Redirected my thought processes.
Again, good companies will do that. Look for every question, no matter how silly, as a way to show how you deal with situations, even ones you may not like. These are the moments for you to shine.
And after you get home, tell your SO/friends/etc. how wacky they are.
Can your pandas library handle that?
Your response is to flip the table and leave? If so, then good riddance.
const isPalindrome(str) { return str === str.split('').reverse().join(''); }
And the post interview notes said bad performance on the isPalindrome() question since I didn't write out my own functions (interviewer did not mention to).
The interviewer probably should have probed you about performance though if their intention was to judge you on that (they're both O(n) time complexity, but split, reverse, and join are generally more intensive).
Id say that close to 0 out off 10 engineers at work including me would get a working program without debugger or print statements.
Just tried in c and got me 2 compiles to get it right. Without the output I would just present a nonworking program.
None of the techniques discussed in this article are even attempting to judge productivity, they are attempts to judge coding ability. It's good that you bring up productivity though; that's what we are really after, isn't it?
>from a short conversation
I'd argue 30 minutes to an hour is not a short conversation. Do you think an imposter could fool you about tech (assuming you are an active programmer) for 30 minutes to an hour?
>it's probably better to see the proof
You're not proving anything except the fact that the candidate has memorized a merge sort algorithm (or whatever trivia you are testing for). What you really want to know is, can they ship?
I think you should at least consider the idea that not only are these tests and homework assignments (past fizz buzz) a poor indicator of ability, they active repel any candidate good enough to be in even reasonable demand. I mean you have a lot of people on not only this thread, but many other threads saying the same thing.
Time for a little reflection, what does your company offer that even a mediocre developer can't get in 20 other places in your city? I mean if I could get "market rates," and a "fine cubicle," and "standard PTO" in 20 places, tell me again why I would bother with this rigamarole?
I have no idea where the idea that having someone come on site for 6+ hours wasting a dozen peoples time became the norm as opposed to talking to someone for 1 or 2 hours and truly speaking with them to understand what they know.
You're completely right, if you can't talk shop and not know when someone is bullshitting you shouldn't be the one interviewing.
How would this even fly in other industries? Are you telling me that someone can bluff their way discussing the intricacies of surgery to other surgeons without looking like a moron? Or discussing particle physics with a researcher and stand on equal footing? I honestly want to hear a conversation where a liar with no programming skills is able to convince a Senior level Software Engineer that they are on equal skill sets.
The best interview experience I had, where I eventually worked for the company, was having an hour conversation with the Engineering Manager who I would be working under then being ask basic programming Qs based on our conversation we had. Everyone in the company was interviewed the same way. IMO the resulting team was very professional and skilled on various levels from various backgrounds. I actually felt like a human at that job and not a person hired because of x thing.
I'll never forget I had an interview where they asked me a question about finding anagrams. At that moment in my life, I've never heard of an anagram or knew what it was. The Interviewer then explaining what it was to me made me feel very humiliated. I completely bombed every question because I had the audacity to not know about this thing where the interviewers knew about thing therefore I should know thing as well. I immediately understood how cultural biases can effect candidates getting jobs. I can only imagine how worst it is for people not from traditional backgrounds in this industry.
I had a candidate for a 3d graphics job, who showed me incredibly impressive things he'd programmed like very realistic water simulations, etc. He talked us through them, was incredibly articulate and clearly knew his stuff.
He completely bombed the coding exercise. It was something like: given 2 hours alone at a computer, with a threejs scene already setup, make it display a few cubes at different heights, colors, etc. Full access to internet, google, etc.
He couldn't get one cube to show up. That's maybe a two line piece of code when given the entire environment already set up, and you can find it by googling Threejs tutorial and copying like the first example.
Ya.
As far as graphics, the only time I was ever fooled was by a front end guy in 2005. He brought really nice looking color printouts of his front ends; beautiful stuff. I was really wowed by it; so much I didn't ask him basic programming problems or follow up questions about his prior work, and that was my fault. I allowed myself to be fooled.
His biggest issue was he was lazy. He had grown accustomed to government contracts where you do a lot of prototyping, but nothing ever went live (at least the contracts he had). We had a very aggressive 3 year schedule to build a sophisticated product and he just couldn't or wouldn't keep up. I had to double my workload and he ended up only doing about 5% when he should have done a third and he required a lot of prodding and hand holding. We still managed to ship on time though, but it was really hard on the other 2 people on the team for 3 years.
I'll never make that mistake again.
Perhaps he really was a very talented developer but your coding exercise was too stressful for him. Shame you missed out on hiring him.
This is not a story to show why we should do coding exercises. It is a story to show why they sometimes don't test the right thing.
1. He knows how to do extremely specialized things in an existing environment, but can't do things outside of that environment.
2. He was presenting work that he had only a partial hand in creating.
3. He is amazing at e.g. C++, but cannot learn even rudimentary new things in Javascript.
...
Some of these stories make him a terrible programmer. Some of them make him an OK programmer for other positions, but weren't relevant for us. None of the stories make him a particularly great programmer.
"Perhaps he really was a very talented developer but your coding exercise was too stressful for him"
Yes, it's possible. A lot of things are possible. But I'm sorry - if someone can't copy-paste a 3 line program from the internet and get it to work, in their own field, for 2 hours, then... I don't know how I could ever design a test on which they won't fail. Including the actual job.