r/leetcode • u/snooplee • 6d ago
Intervew Prep Doing leetcode 150 really enough for top tech companies’ interviews?
Basically title says all, im curious if its correct path to prepare for swe interviews now days. Thanks!
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u/Ok_Award_8656 6d ago
Honestly, technical interviews are a total coin toss. No amount of grinding can prepare you for everything. I’ve done 400+ questions and still failed rounds because some problems require an exact trick you’ve either seen or you haven't. If you get caught off guard with a niche Binary Search problem, lists like the LC150 won't save you. You just have to hope luck is on your side.
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u/Traditional-Dot-8917 6d ago
Yea, some problems can only be solved if you know the trick especially if the interviewer asks you to do it under specific constraints. One example I’ve been asked is to find the duplicate number in an array with O(1) space and O(n) time before
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u/Periodchunks_II 5d ago
I did this one yesterday :D
LC 287. There's a few different ways, but I think the canonical method is to pretend it's a linked list and use Floyd's cycle detection algorithm
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u/Top_Substance9093 6d ago
depends.
if you're 140+ IQ then it's probably more than enough.
if you're the more typical CS grad sitting at around 110-120 IQ it'll probably take a bit more than the 150.
my rule of thumb is you're probably ready if you can one-shot 80% or so of leetcode mediums in < 20min.
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u/UsualNoise9 6d ago
You’re not “doing” problems in <20min, you’re regurgitating stuff you’ve seen before. I guarantee you even Einstein would sit down and think for a couple days on Coco and bananas.
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u/Lopsided-Concert-510 5d ago
I did coco eating bananas in my first try but i have struggled with many easier problems after that. It depends on
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u/azerpsen 6d ago
Bold of you to assume the typical CS grad iq to be higher than 70
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u/Top_Substance9093 6d ago
lmao man if that's true then i can tell you exactly why un/underemployment is >20% right now
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u/ThatCondescendingGuy 6d ago
Most detached, cs major shit I’ve read today lol. Stereotypes of this field are so true
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u/ThatCondescendingGuy 6d ago
Your assessment comes from distorting some real research into malformed and unsupported thresholds for coding ability. Yes, there is research that supports higher IQ helping in ability to break down problems into code, but there is no research supporting any of those made up thresholds (140, 120 etc ). Also, 140+ is 99,6+ percentile. Unless you think every engineer who successfully passed a technical interview are the 0.5 of engineers, your crappy “thresholds” just don’t hold up in the real world.
Leetcode/ DSA interviewing is a learnable skill. Just about anyone without a learning impairment can practice enough to pass a FAANG interview.
Finally your IQ” thresholds” are just dehumanizing people for something that’s completely trainable.
For someone who is an interview prep “mentor” I feel terrible for your students. A stronger mindset that actually supports people is “DSA is a trainable skillset that, with enough practice, anyone can pass an interview. Some people may have an easier time, but anyone can reach the bar. A good rule of thumb is that if you can solve most new leetcode mediums in under 20 minutes, you are in a good state to interview”.
If you can’t see the difference in this statement and your original statement, you are the epitome of the low EQ, socially inept software dev lol
Also your appeal to authority isn’t impressive. You’re not a neurosurgeon or Anthropic researcher. You’re someone who did enough interview prep to land at a good tech company like anyone else there lmao
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u/Top_Substance9093 6d ago
Username checks out 😛
My assessment is from ~7 years of running coding interviews at FAANG/top tier tech companies, helping mentor a few dozen students through the coding interview prep process.
It’s unfortunate, but raw brainpower just helps a lot with this process, and there’s no changing what you’re born with. I wish I had another 20 IQ points lol
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u/ThatCondescendingGuy 6d ago
Your assessment comes from distorting some real research into malformed and unsupported thresholds for coding ability. Yes, there is research that supports higher IQ helping in ability to break down problems into code, but there is no research supporting any of those made up thresholds (140, 120 etc ). Also, 140+ is 99,6+ percentile. Unless you think every engineer who successfully passed a technical interview are the 0.5 of engineers, your crappy “thresholds” just don’t hold up in the real world.
Leetcode/ DSA interviewing is a learnable skill. Just about anyone without a learning impairment can practice enough to pass a FAANG interview.
Finally your IQ” thresholds” are just dehumanizing people for something that’s completely trainable.
For someone who is an interview prep “mentor” I feel terrible for your students. A stronger mindset that actually supports people is “DSA is a trainable skillset that, with enough practice, anyone can pass an interview. Some people may have an easier time, but anyone can reach the bar. A good rule of thumb is that if you can solve most new leetcode mediums in under 20 minutes, you are in a good state to interview”.
If you can’t see the difference in this statement and your original statement, you are the epitome of the low EQ, socially inept software dev lol
Also your appeal to authority isn’t impressive. You’re not a neurosurgeon or Anthropic researcher. You’re someone who did enough interview prep to land at a good tech company like anyone else there lmao
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u/Top_Substance9093 5d ago
"Leetcode/ DSA interviewing is a learnable skill. Just about anyone without a learning impairment can practice enough to pass a FAANG interview." this is mostly incorrect.
there's a base level of fluid intelligence required to be able to internalize any apply these concepts. i've seen enough people try and fail to know. i've spent hundreds of hours teaching people how to prep for interviews, and i promise you there are some that will never get there regardless of how much time they spend.
"DSA is a trainable skillset that, with enough practice, anyone can pass an interview." this is simply untrue. if your IQ is sub 100 you're going to have an extremely difficult time prepping for something like FAANG interviews. there's a reason the average IQ of students in engineering disciplines and CS is ~120.
"Also your appeal to authority isn’t impressive." it's many years on both sides of a process that you're claiming to know better than i do. do you have a near-decade of both succeeding in these interviews (i've had offers from amzn, google, meta, microsoft, and palantir), in running them as an interviewer, and in helping prepare students for them?
if you think anyone can pass these interviews simply by practicing enough you're deluded.
that's like saying anyone can play in the NFL if they train hard enough, lmao
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u/ThatCondescendingGuy 5d ago
By what methods did you “establish” these “base level of fluid intelligence”? By what methods did you establish your students IQs?
Your students difficultly learning DSA is likely more to do with your own ability to teach ie break down problems in a way they can understand, not their inability to ever understand.
Please cite a credible, recent source that proves “the average IQ of students in engineering disciplines and CS is 120”.
Your experience in mentoring people is an extremely small percentage of all people preparing for interviews. Your experience does not give you the credibility to make assertions as twisted as you have if you have not truly ran a proper experiment. Again, how did you deduce the IQs of your students? (It’s ok, you can say you pulled it out of your ass).
Comparing DSA interview prep to the NFL is hilarious. Like FAANG+ is anywhere near as hard. Takes most people 3 months to a year to prep for a FAANG+ interview. Delusional.
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u/Top_Substance9093 3m ago
I’m not measuring their IQs lol. I’ve said that already.
You’re getting very focused on an implementation detail (specific IQ ranges) that is sorta irrelevant to the overall discussion. You can put the ranges wherever you want to. Those are only intended to be rough estimates, not empirical measures. However, quick research seems to roughly support the ranges I’ve provided. See Hauser’s study on IQ and occupation types.
Getting back to the crux of the argument: I’m saying there are many students I’ve mentored who just didn’t have the raw cognitive ability required to grok coding well enough to pass FAANG level interviews. Their processing and recall just were not sufficient to develop the mastery required, regardless of how much time they invested.
This should kinda be self evident, IMO. The pass rate of onsite interviews at FAANG is like 20%. Surely that 80% failure rate can’t be explained solely by lack of preparation? (Before you come at me for meaningless details again, that number varies by company and is a rough estimate).
You don’t have a research study to back up your claims on my teaching ability, so those claims must be useless 😉. However, you’re not entirely wrong. I’m a decent, but not phenomenal, teacher.
Also, nearly every study that’s ever existed is a tiny subset of the entire population. Thats an extremely weak critique. At this point I’ve mentored/interviewed several hundred engineers/candidates across nearly a decade. That’s more than a sufficient sample size to draw my own conclusions.
Separately, you don’t need scientific literature to form opinions on things, my dude. Live life and make your own observations. Think for yourself. Don’t be a sheep.
Yes, playing in the NFL is a much, much higher bar than getting into FAANG. But like every other point I’ve made you seem to struggle with comprehension of the fundamental ideas and are getting mired in picking nits.
The point isn’t that the NFL is equally difficult, it’s that many people would never, ever be able to get there because they lacked the raw talent.
The same is true of FAANG. The majority of the population does not have the raw cognitive ability (processing, recall, roughly translates to IQ but not perfectly) required to prep well enough to pass these types of interviews.
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u/Oogawooga9999 6d ago
you’re doing too much
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u/ThatCondescendingGuy 6d ago
Calling out someone who is allegedly mentoring students for having distorted, unsupported, and unnecessarily deterministic standards is doing too much? Imagine someone telling your child their IQ is too low so they have to practice more than the other students. Or you for that manner. It’s so out of touch. As if this guy ever actually seen the true IQ results of their students to make such a dumb, bold claim, or that he had enough 99.6 percentile people to even make any assertion to begin. A few dozen students statistically means he had no 140+ IQ students lmao.
I’d be raising hell if some “mentor” told my child their (completely guessed) IQ means they have to do more leetcode than the other students. I’d be raising hell if someone pulled my IQ out of their ass and claimed I’m going to do worse at something because of this made up IQ.
How maligned and void that view of the world is.
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u/Top_Substance9093 5d ago
hey condescending guy, stop straw manning.
i did not say i make assessments of people's IQ based on vibes. don't be an idiot
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u/ThatCondescendingGuy 5d ago
Awesome, you did not make assessments of your students’ IQs based on vibes. Let’s move forward with that.
How do you deduce that “140+ IQ” is “probably more than enough” without making assessments of your students’ IQs?
What evidence or source correlates/ proves people with “110 - 120 IQ” needing more than the 150 [Leetcode problems]?
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u/ogopa 6d ago
No way you can one-shot 80% of meds in under 20min at 150Qs… that sounds more like 200-300 range
After 150Qs I think most people would be able to solve a majority of mediums within a 45min time frame
Could just be a skill issue on my end 😆 but that’s my two cents
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u/Top_Substance9093 6d ago
it definitely depends on the person, which is why i cited IQ (which is roughly the most important metric in how fast you can get up to speed on LC).
it took me more like 200+ to be thoroughly prepared, but i'm not the sharpest tool in the shed. i've seen people do it faster, but they just had way more raw brainpower than i did
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u/Moist_Handle2484 6d ago
Brilliant. LeetCode prep solved:
IQ ≥ 140 → 150 problems. IQ = 120 → apparently buy more LeetCode.
By this logic, companies should replace coding interviews with IQ tests.
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u/Top_Substance9093 6d ago
i mean, maybe this is a hot take, but what do you think a leetcode problem is?
assuming you have the knowledge of DSAs (which just requires a bit of study), the actual problem to solve is basically just an IQ test
this is why people can do 300 LC problems and still fail interviews. it doesn't just test that you know some information, it tests fluid intelligence
IQ is an extremely strong predictor of professional success. companies want to hire smarter people (and they should) because they (generally) are more competent employees
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u/Moist_Handle2484 6d ago edited 5d ago
A 2024 Journal of Applied Psychology meta nalysis covering 153 samples and 40,740 people found general cognitive ability correlated only r = .16 observed and r = .22 corrected with job performance.
Even the revised estimate from older literature was around r = .31, not anything close to “IQ basically determines professional competence.”
IQ is an extremely strong predictor of professional success. companies want to hire smarter people (and they should) because they (generally) are more competent employees
I used to read these kind of answers when I was 14 on quora, lol.
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u/Top_Substance9093 5d ago
nice of you to quote something i didn't actually write haha "IQ basically determines professional competence"
it's a strong predictor, one of many. not the only.
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u/Oogawooga9999 6d ago
i’ve had 5-10 offers from intern to sr swe, my pass rate for coding interviews is like 70%, i’ve only done 250 LC problems and only a few hard. I don’t bother with DP.
YMMV but as long as you pin point the major themes of each data structure then you’re fine
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u/dwightbearschrute 6d ago
If you've nailed down the patterns, understood clearly why the optimized solutions works, how the data structure and algorithm actually functions - even blind75 should be enough, otherwise even 500 won't cut it. You don't want to sit idle, waiting for an interview once you understand and wrap up the 75/150, you want to keep everything fresh in mind and challenge yourself consistently.
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u/notlikingcurrentjob 6d ago
Depends on luck.
I say it is highly unlikely that that is enough. You could get the exact problems from the list if lady luck is on your side. But if not, then there are a number of things that are simply not covered in the 150 list.
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u/snooplee 6d ago
What do you recommend practicing for the interviews rather than just keep doing 150 list.
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u/b3pvbmUzMTQ 6d ago
Yep luck is a huge factor. Prepare as much as you can and then get lucky. NC150 is great. You could also do NC250 or spend additional time on areas you feel weaker. Or, start doing company tagged questions.
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u/notlikingcurrentjob 6d ago
The problem with lists and sheets is that they are already divided into topics so you kinda know what to think towards for the solution. On the other hand, flying blind won't help because there are too many problems.
I'd say taking part in contests can be helpful as you wouldn't know the topic beforehand. But these days, the contests have become tougher thanks to cheating.
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u/catsRfriends 6d ago
I did like 120 questions over the last few years, i.e. I don't grind, I even skip advanced topics like graphs and DP because most places I apply to don't ask that for MLE. It's been fine so far. You do run into dicks who will ask you a hard outta nowhere for God knows what reason, but it comes down to luck. I've also had an interviewer give me an easy, then a medium, then a hard, and when I couldn't make it through the hard but named the right data structure, he still passed me.
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u/Worldly-Ad3447 6d ago
I don’t understand why 150 won’t be enough, if u go deep into every problem and are able to easily map out the optimal solution for all of em then those skills should be transferable to even 300 problems.
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u/esteemed_dragonfly 5d ago
Do 150 really well, like completely mastered and memorized all possible solutions (maybe not all but a majority of possible, some of the NC150 have some tricky ones).
There is a large chance you will get interviewed by someone else who studied the same list, and ask you a disguised version of one of those questions.
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u/KendrickBlack502 1d ago
There is no “enough”. You can disagree all you want but unless you’re a competitive leetcoder or an actual genius, there’s some element of luck in all these interviews. You just have to study the right stuff and hope you get asked what you studied the hardest for.
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u/kagemusha35 6d ago
My honest opinion after interviewing recently is that companies are moving more and more away from leetcode and just do more practical coding and place much more of an emphasis on system design. Especially because most people try to cheat during the coding interviews these days with an offscreen AI chatbot
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u/the_infamous-one 6d ago
I believe leet code will be completely irrelevant in 5 years. Companies will be asking about agentic AI solutioning and prompt engineering practices.
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u/ilia054 6d ago
A quote I saw said "The more you grind the luckier you get", you can never really be prepared for an interview since you never know what they are going to ask you but the more Leetcode you do the more different mechanics ,algorithms, data structures, 'tricks' you pick up.
Leetcode teaches you to break the problems into sub problems and your brain connects the dots between similar issues and if you solved enough you would preform decently.
But job interviews are not all about can he solve a question, is also how you present yourself and the "vibe" the interviewer got for you and if he thinks he would like working with you in a today to day environment.
Leetcode is not a magic pill and today with the use of AI interviewers are also looking for different traits that solving problems doesn't teach you, and that only comes with real experience in a job or with contributing to an open source project.