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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

#101

Post by CamperBob2 »

I implemented the simple greedy algorithm and immediately fell into the trap of the question: the greedy algorithm only works for "well-behaved" denominations. If the coin values were [10, 9, 1], then making 37 cents would take 10 coins in the greedy algorithm but only 4 coins optimally (10+9+9+9).

That's a bad algorithm, then, not a greedy algorithm. Wouldn't a properly-implemented greedy algorithm use as many coins as possible of a given large denomination before dropping back to the next-lower denomination?

If a candidate's only options are to either use a constraint solver or to implement a naïver-than-usual greedy algorithm, well, sorry, but that's a no-hire.

Re: Many hard LeetCode problems are easy constraint problems

#102

Post by another_twist »

strangattractor wrote: post #97
tracker1 wrote: post #77

My biggest problem with leetcode type questions is that you can't ask clarifying questions. My mind just doesn't work like most do, and leetcode to some extent seems to rely on people memorizing leetcode type answers. On a few, there's enough context that I can relate real understanding of the problem to, such as the coin example in the article... for others I've seen there's not enough there for me to "get" the ques…

IMO leetcode has multiple problems. 1. People can be hired to take the test for you - surprise surprise 2. It is akin to deciding if someone can write a novel from reading a single sentence.

Hiring people for the test is only valid for online assessment. For an onsite, its very obvious if the candidates have cheated on the OA. I've been on the other side and its transparent.

> It is akin to deciding if someone can write a novel from reading a single sentence.

For most decent companies, the hiring process involves multiple rounds of these challenges along with system designs. So its like judging writing ability by having candidates actually write and come up with sample plots. Not a bad test.

Re: Many hard LeetCode problems are easy constraint problems

#103

Post by erikerikson »

vkou wrote: post #95
erikerikson wrote: post #76

Earlier quoted context omitted.

I think this is one of the more true answers but can you be more specific? Like in race? Like in wealth? Like in defection willingness? Like in corruption? Asking for a friend who is regularly identified as among the most skilled but feels their career has been significantly derailed by this social phenomenon.

Like in 'can solve a leetcode question quickly', because that's what the interview rubric asks them to test for.

That is the acceptable public answer of course but it is a mind stopper. Obviously the definition comes from some person with some set of motivations and this seems to ignore that real and pertinent question.

Re: Many hard LeetCode problems are easy constraint problems

#104

Post by CamperBob2 »

Der_Einzige wrote: post #30
dataflow wrote: post #21

My beef with someone using a constraint solver here is that they almost certainly wouldn't be able to guarantee anything about their solution other than that, if it produces an output, it will be correct. They won't be able to guarantee running time, space usage, or (probably for most tools) even a useful progress indicator. The problem isn't merely that they used another tool - the problem is that they abstracted aw…

[flagged]

That's an en-dash, not an em-dash

Re: Many hard LeetCode problems are easy constraint problems

#105

Post by another_twist »

garrettgarcia wrote: post #100
tracker1 wrote: post #77

My biggest problem with leetcode type questions is that you can't ask clarifying questions. My mind just doesn't work like most do, and leetcode to some extent seems to rely on people memorizing leetcode type answers. On a few, there's enough context that I can relate real understanding of the problem to, such as the coin example in the article... for others I've seen there's not enough there for me to "get" the ques…

> My biggest problem with leetcode type questions is that you can't ask clarifying questions. Huh? Of course you can. If you're practicing on leetcode, there's a discussion thread for every question where you can ask questions till the cows come home. If you're in a job interview, ask the interviewer. It's supposed to be a conversation. > I wouldn't even mind the studying on leetcode types sites if they actually had…

> My biggest problem with leetcode type questions is that you can't ask clarifying questions.

Yeah this one confused me. Not asking clarifying questions is one of the sureshot ways of failing an interview. Kudos if the candidates ask something that the interviewers havent thought of, although its rare as most problems go through a vetting process (along with leak detection).

Re: Many hard LeetCode problems are easy constraint problems

#106

Post by another_twist »

lawlessone wrote: post #96
tracker1 wrote: post #77

My biggest problem with leetcode type questions is that you can't ask clarifying questions. My mind just doesn't work like most do, and leetcode to some extent seems to rely on people memorizing leetcode type answers. On a few, there's enough context that I can relate real understanding of the problem to, such as the coin example in the article... for others I've seen there's not enough there for me to "get" the ques…

The one's i've gotten have all seemed more like tests of my puzzle solving skills than coding. The worst ones i've had though had extra problems though: one i was only told about when i joined the interview and that they would be watching live. One where they wanted me streaming my face the whole time (maybe some people people are fine with that) And one that would count it against me if i tabbed to another page. So…

You can make up API calls which you can say you'd implement later. As long as these are not tricky blocks, you'll be fine.

Re: Many hard LeetCode problems are easy constraint problems

#107

Post by Planktonne »

chaboud wrote: post #24
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…

When I interview with problem solving problems, the point is to understand how the candidate thinks, communicates, and decomposes problems. Critically, problem solving questions should have ways to progressively increase and decrease difficulty/complexity, so every candidate "gets a win" and no candidate "dunks the ball". Interviewers learn nothing from an instant epiphany, and they learn next to nothing from someone…

> Critically, problem solving questions should have ways to progressively increase and decrease difficulty/complexity, so every candidate "gets a win" and no candidate "dunks the ball".

Absolutely agree. When I interview, I start with a simple problem and add complexity as they go. Can they write X? Can they combine it with Y? Do they understand how Z is related?

Re: Many hard LeetCode problems are easy constraint problems

#108

Post by silisili »

another_twist wrote: post #98
tracker1 wrote: post #77

My biggest problem with leetcode type questions is that you can't ask clarifying questions. My mind just doesn't work like most do, and leetcode to some extent seems to rely on people memorizing leetcode type answers. On a few, there's enough context that I can relate real understanding of the problem to, such as the coin example in the article... for others I've seen there's not enough there for me to "get" the ques…

Its not really memorizing solutions. Yes you can get quite far by doing so but follow ups will trip people up. However if you have memorized it and can answer follow ups, I dont see a problem with Leetcode style problems. Problem solving is about pattern matching and the more patterns you know and can match against, the better your ability to solve problems. Its a learnable skill and better to pick it up now. Persona…

It is and isn't. I'd argue it's not memorizing exact solutions(think copy paste) but memorizing fastest algos to accomplish X.

And some people might say well, you should know that anyways. The problem for me is, and I'm not speaking for every company of course, you never really use a lot of this stuff in most run of the mill jobs. So of course you forget it, then have to study again pre interview.

Problem solving is the best way to think of it, but it's awkward for me(and probably others) to spend minutes thinking, feeling pressured as someone just stares at you. And that's where memorizing the hows of typical problems helps.

That said, I just stopped doing them altogether. I'd passed a few doing the 'memorizing' described above, only to start and realize it wasn't at all irrelevant to the work we were actually doing. In that way I guess it's a bit of a two way filter now.

Re: Many hard LeetCode problems are easy constraint problems

#109

Post by another_twist »

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…

No its not a measure of cleverness. Its about whether you can break down problems and apply common methods. Thats the entire job. Its a learnable skill and honestly resisting learning because of personal biases is a red flag in my book.
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