More relevant to the topic at hand, I feel like I didn’t put that much thought into designing my interview questions, but I’m always astounded when I read these sorts of descriptions of other interview questions. There should perhaps be some formal training or certification or something for asking good engineering interview questions.
"How do mobile phone towers work?"
People steal/phish resumes off sites all the time, and it is really hard to remain polite while listening to someone lie. I've met 300lb round cons that claim they regularly climb broadcast towers =3
"What number am I thinking of?"
Smart developers - really smart developers are always right. Truly great developers have seen this sort of problem before and know how to attack it - they need no fancy questions or "deeper understanding". They simply hit the whiteboard, do the logic and output the answer.
Don't settle for anything except A players.
Same with your last sentence.
But assuming you are unwilling to answer any additional questions, the correct solution is to simply brute force every number up from 0 and its negative.
I don't think this is a good interview question, but I do think it is interesting as a thought exercise.
I bet that perhaps 25% of candidates could actually answer the question correctly, even if they didn't know anything about Schelling points. It could also lead to some nice discussions about how to solve an open-ended problem, probability distributions, strategies for maximizing payoffs when making decisions in the face of uncertainty, and so on. The question is so bad, it's actually kind of good.
% isIt3
10
0
6
4
8
0
9
5
I found three
----
proc isIt3 {} {
variable 3 [expr {int(rand()*12)}]
switch $3 {
3 { puts "I found three" }
default { puts "$3" ; isIt3 }
} ;# end switch
} ;# end proc
Disastrous in the hands of an interviewer who’s looking for a one word answer.
If I know about it as well, then we can have a really deep discussion, if I don’t- then I can learn something new.
The aim when interviewing is to check how well / deeply the interviewee can think through a problem.
If we pick a topic that they don’t have deep knowledge - they can either stumble and freeze emotionally, or hallucinate something just to appear smart. At this point it is an examination not an interview. And sure some people are capable enough to get to an answer, but that’s more of a lottery than a real analysis.
It usually boils down to how often have they interviewed before and been in a similar situation. And “people who have interviewed a lot” is hardly a metric I want to optimise for.
Now picking something they know or have expressed interest or passion in, this means we are sure to have more signal than noise. If the interviewee’s description is more of a canned response - then I delve deeper or broader.
“I’ve managed to solve this issue by introducing caching” - “Great, are there other solutions? How do you handle cache invalidation, what are the limits? What will you do if the load increases 10 fold, would you need to rethink the solution?”
The topic of the database came up, and I asked "Do we care more about consistency or availability?".
He responded back with "we want both".
I said "I mean, I would like both too but I'm pretty sure we can only get one"
He disagreed and we went back and forth, and eventually I pull out my phone and pull up the Wikipedia for CAP theorem. He eventually (and begrudgingly) agreed and said "umm, I guess availability", so I used Cassandra and moved on with it, though five minutes were wasted with this pointless argument.
To be fair, they did make me an offer, and it was even a decent enough offer (though I ended up taking a different job), but I remember being kind of flabbergasted that I had to explain CAP theorem to a person who had like a decade more experience than I did. It's not like CAP theorem is this super deep arcane topic; I'm pretty sure it's one of the first things you learn about when getting into distributed systems. It was certainly one of the first thing that I learned about.
More importantly I appreciate the OP for describing lessons learned through this hard experience. I worked in finance: Cassandra is no kind of answer for systems of record
Thanks
Why does it require 30,000 servers to process millions of daily transactions? Is there a typo in the amount?
(till this day, I can walk into a shop, look at the POS screen and identify if its one of those visual basic/PHP/windows XP compatibility mode required stuff).
Sometimes you gotta fire your interviewer.
I feel this is misleading. I think a reasonable definition of a 'good' engineer is engineer in the 75th percentile and above for their craft. You can debate other definitions, I'm not saying this is the only reasonable one. But by this definition, I think you can immediately see that it is hard -- given 4 engineers, we expect that only one of them is "good". And what if your standards are higher? What if you only want _great_ engineers? I can't believe that it's easy.
1. Person who cares 2. Person who is knowledgeable 3. These two must be the same person!
Many, many forces lined up against meritocracy. All the incumbents, for example, tend to have something to lose, but it's the incumbents who decide if you are hired.
It's a miracle that there are any good companies once the original owners are gone.
naming "cassandra" is not designing a database.
it feels like there was some miscommunication along the way
You sweet summer child.
The things I've seen at certain worksites...
A "database" that starts to fall if the ring in the cluster becomes choked? Draining a broken Cassandra ring and under high load is hell and ball clenching.
Especially hoping that another Cassandra node doesn't fail under high load. Pish, Erlang and mnesia.
> The CAP theorem is not a suggestion. It’s a mathematical proof.
> this is not a philosophical inconvenience. It’s a compliance violation.
@dang, i thought we just banned AI written blog posts?
I know I will get downvoted for this everytime I post this comment, but I'm sick and tired of 80% of everything being written/heavily edited by AI.
Can the author not just use his own words? Is he really that bad at writing? But somehow the content is supposed to ne worth my time?
I'd rather read the prompt instead, so I know which parts the author actually meant to say, rather than wondering which parts the AI invented to make it sound flowery and punchy, the Tiktok style of prose.
Can you post more substantial comments than?:
https://news.ycombinator.com/item?id=47360241
https://news.ycombinator.com/item?id=47355553
https://news.ycombinator.com/item?id=47355564
https://news.ycombinator.com/item?id=47345091
https://news.ycombinator.com/item?id=47343706
https://news.ycombinator.com/item?id=47337595
https://news.ycombinator.com/item?id=47333400
https://news.ycombinator.com/item?id=47269468
And the lesson of the blog is why forcing LLM usage is stressful to some engineers. Most implementations are in a quantum state and the back and forth to have clear requirements is what can make the wave function collapse. We know all the possible answers , but all of them are equally valid.
We could go with the LLM route and just do a quick guess on the answer, but "Accountability" and "Professionalism" prevent us from doing so.