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Many hard LeetCode problems are easy constraint problems

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Re: Many hard LeetCode problems are easy constraint problems

#41

Post by erikerikson »

corimaith wrote: post #13
kccqzy wrote: post #5

Great insight. But this is sadly not applicable to interviews. > It's easy to do in O(n^2) time, or if you are clever, you can do it in O(n). Or you could be not clever at all and just write it as a constraint problem This nails it. The point of these problems is to test your cleverness. That's it. Presenting a not-clever solution of using constraint solvers shows that you have experience and your breadth of knowledg…

>The point of these problems is to test your cleverness. No it's just memorization of 12 or so specific patterns. The stakes are too high that virtually everyone going in will not be staking passing on their own inherent problem solving ability. LeetCode has been so thoroughly gamified that it has lost all utility of differentiability beyond willingness to prepare.

Given this consider that LeetCode solving is rarely ever part of your work. So then, what are they selecting for with the habit?

Re: Many hard LeetCode problems are easy constraint problems

#42

Post by erikerikson »

jkubicek wrote: post #39
corimaith wrote: post #13

Earlier quoted context omitted.

>The point of these problems is to test your cleverness. No it's just memorization of 12 or so specific patterns. The stakes are too high that virtually everyone going in will not be staking passing on their own inherent problem solving ability. LeetCode has been so thoroughly gamified that it has lost all utility of differentiability beyond willingness to prepare.

In defense of questions like this, “willingness to prepare” is a significant differentiator

But what is it differentiating? And is it really the best evidence of willingness to prepare? My MSc and BA on the topics, my open source contributions, two decades of industry experience... Those aren't evidence of not only willingness but execution of preparation?

Re: Many hard LeetCode problems are easy constraint problems

#43

Post by roadside_picnic »

kccqzy wrote: post #5

Great insight. But this is sadly not applicable to interviews. > It's easy to do in O(n^2) time, or if you are clever, you can do it in O(n). Or you could be not clever at all and just write it as a constraint problem This nails it. The point of these problems is to test your cleverness. That's it. Presenting a not-clever solution of using constraint solvers shows that you have experience and your breadth of knowledg…

> The point of these problems is to test your cleverness.

Last round I did at Meta it was clearly to test that you grinded their specific set of problems, over and over again, until you could reproduce them without thinking. It's clear because the interviewers are always a bit surprised when you answer with whatever is not the text-book approach on both leetcode and on the interview guide they studied.

Cleverness is definitely not high on the list of things they're looking for.

Re: Many hard LeetCode problems are easy constraint problems

#44

Post by bee_rider »

corimaith wrote: post #13
kccqzy wrote: post #5

Great insight. But this is sadly not applicable to interviews. > It's easy to do in O(n^2) time, or if you are clever, you can do it in O(n). Or you could be not clever at all and just write it as a constraint problem This nails it. The point of these problems is to test your cleverness. That's it. Presenting a not-clever solution of using constraint solvers shows that you have experience and your breadth of knowledg…

>The point of these problems is to test your cleverness. No it's just memorization of 12 or so specific patterns. The stakes are too high that virtually everyone going in will not be staking passing on their own inherent problem solving ability. LeetCode has been so thoroughly gamified that it has lost all utility of differentiability beyond willingness to prepare.

Yeah, it tests if the candidate enjoys the programming-adjacent puzzle game of LeetCode, which is a perfectly decent game to play, but it is just a signal.

If somebody grinds LeetCode while hating it, it signals they are really desperate for a job and willing to jump through hoops for you.

If somebody actually enjoys this kind of stuff, that is probably a signal that they are a rare premium nerd and you should hire them. But the probably play Project Euler as well (is that still up?).

If somebody figures out a one-trick to minmax their LeetCode score… I dunno, I guess it means they are aware of the game and want to solve it efficiently. That seems clever to me…

Re: Many hard LeetCode problems are easy constraint problems

#45

Post by viccis »

kccqzy wrote: post #5

Great insight. But this is sadly not applicable to interviews. > It's easy to do in O(n^2) time, or if you are clever, you can do it in O(n). Or you could be not clever at all and just write it as a constraint problem This nails it. The point of these problems is to test your cleverness. That's it. Presenting a not-clever solution of using constraint solvers shows that you have experience and your breadth of knowledg…

>The point of these problems is to test your cleverness.

In my experience, interviewers love going to the Leetcode "Top Interview 150" list and using problems in the "Array String" category. I'm not a fan of these problems for the kind of jobs I've interviewed for (backend Python mostly), as they are almost always a "give me a O(n) runtime O(1) memory algorithm over this array" type challenge that really doesn't resemble my day to day work at all. I do not regularly do in-place array algorithms in Python because those problems are almost always handled by other languages (C, Rust, etc.) where performance is critical.

I wish interviewers would go to the "Hashmap" section for interviews in Python, JavaScript, etc., type of languages. They are much less about cleverness and more about whether you can demonstrate using the appropriate tools in your language to solve problems that actually do resemble ones I encounter regularly.

There's also the problem of difficulty tuning on some of these. Problem 169 (Majority Element) being rated "Easy" for getting a O(n) runtime O(1) memory solution is hilarious to me. The algorithm first described in 1981 that does it (Boyer–Moore majority vote algorithm) has a Wikipedia page. It's not a difficult to implement or understand algorithm, but its correctness is not obvious until you think about it a bit, at which point you're at sufficient "cleverness" to get a Wikipedia page about an algorithm named after you. Seems excessive for an "Easy" problem.

Re: Many hard LeetCode problems are easy constraint problems

#46

Post by hackingonempty »

Der_Einzige wrote: post #27
holden_nelson wrote: post #3

I feel like if I'm being asked this in an interview, they're not asking me to use a constraint solver, they're asking me to _write_ a constraint solver. Just for a specific constraint problem, not a more general constraint solver.

If someone solves a leetcode hard with a constraint solver and you don't hire them, you are an idiot. Do you know how few people in this world even know what a constraint solver is, let alone how to correctly define the problem into one? I used a constraint solver to solve a homework problem once in my CS degree 3rd year. My god just writing the damn constraints was a huge cognitive load!

I did this, wrote an Essence-prime program to generate Minion solver code for a simple instance of the knapsack problem, as part of a startups "solve one of these and get an interview" challenges. Because I had used those tools recently for a contract job (and wrote/presented a paper on invitation of the solver authors,) I thought it would be fun and didn't really want the job. Got an interview but every dev was like "why did you use a cannon to swat a fly?" and were clearly concerned that without strict supervision I would create baroque towers of garbage for them to clean up.

Re: Many hard LeetCode problems are easy constraint problems

#47

Post by tjpnz »

jkubicek wrote: post #39
corimaith wrote: post #13

Earlier quoted context omitted.

>The point of these problems is to test your cleverness. No it's just memorization of 12 or so specific patterns. The stakes are too high that virtually everyone going in will not be staking passing on their own inherent problem solving ability. LeetCode has been so thoroughly gamified that it has lost all utility of differentiability beyond willingness to prepare.

In defense of questions like this, “willingness to prepare” is a significant differentiator

That willingness to prepare doesn't reconcile with the realities of parenthood and all of the other responsibilities someone in their thirties may have. Consistently finding that time will be a huge ask, especially if you haven't worked on those problems in a while.

Re: Many hard LeetCode problems are easy constraint problems

#48

Post by xenocratus »

Der_Einzige wrote: post #27
holden_nelson wrote: post #3

I feel like if I'm being asked this in an interview, they're not asking me to use a constraint solver, they're asking me to _write_ a constraint solver. Just for a specific constraint problem, not a more general constraint solver.

If someone solves a leetcode hard with a constraint solver and you don't hire them, you are an idiot. Do you know how few people in this world even know what a constraint solver is, let alone how to correctly define the problem into one? I used a constraint solver to solve a homework problem once in my CS degree 3rd year. My god just writing the damn constraints was a huge cognitive load!

> If someone solves a leetcode hard with a constraint solver and you don't hire them, you are an idiot.

I do hope you're exagerating here, but in case you aren't: this is an extremely simplistic view of what (software) engineers have to do, and thus what hiring managers should optimize for. I'd put "ability to work in a team" above "raw academic/reasoning ability" for the vast majority of engineering roles, any day.

Not that the latter doesn't matter, of course, but it's by no means the one and only measure.

Re: Many hard LeetCode problems are easy constraint problems

#49

Post by itissid »

Long time ago, just for fun, I wrote a constraint solver problem that could figure out which high yield banks to put money into that were recommended on doctor of credit(https://www.doctorofcredit.com/high-interest-savings-to-get/) based on I played it for a while when interest rates were really low and used the thing for my own rainy day savings(I did get tired changing accounts all the time)

Re: Many hard LeetCode problems are easy constraint problems

#50

Post by LordDragonfang »

tjpnz wrote: post #47
jkubicek wrote: post #39

Earlier quoted context omitted.

In defense of questions like this, “willingness to prepare” is a significant differentiator

That willingness to prepare doesn't reconcile with the realities of parenthood and all of the other responsibilities someone in their thirties may have. Consistently finding that time will be a huge ask, especially if you haven't worked on those problems in a while.

I mean, it would be illegal for them to state it outright, but most companies would prefer not to hire people with kids and other responsibilities. That's the whole reason there are specific discrimination laws for that.
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