Making an Algorithm Faster

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  • Опубліковано 8 лис 2024
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КОМЕНТАРІ • 223

  • @ThePrimeTimeagen
    @ThePrimeTimeagen Місяць тому +1521

    LETS GO! I HAVE MADE IT!!!

  • @tommyshelby6277
    @tommyshelby6277 Місяць тому +611

    bro primeagened primeagen

  • @sahilverma_dev
    @sahilverma_dev Місяць тому +526

    "from this little youtuber primeOgen"

    • @PP-ss3zf
      @PP-ss3zf Місяць тому +13

      trying to understand if hes just trolling, he said it so seriously

    • @sahilverma_dev
      @sahilverma_dev Місяць тому +2

      @@PP-ss3zf what do you think

    • @PP-ss3zf
      @PP-ss3zf Місяць тому +6

      @@sahilverma_dev my comment.. thats what i think

    • @Iron_spider99
      @Iron_spider99 Місяць тому +1

      ​@@PP-ss3zf think some more

    • @yassinesafraoui
      @yassinesafraoui Місяць тому +7

      @@PP-ss3zf he's obviously trolling, he knows him

  • @landonkryger
    @landonkryger Місяць тому +43

    A similar video by Matt Parker (Stand-up Maths) "Someone improved my code by 40,832,277,770%." I was part of the team that optimized his 1 month solution down to 300 microseconds. We submitted ours kind of late so he wasn't able to cover our big algorithmic changes, but many of the techniques you mention here applied there as well.

  • @haronxbelghit
    @haronxbelghit Місяць тому +146

    18:00 no coincidence, the range from 97 to 122 falls between (32*3 = 96) and (32* 4 = 128), meaning the remainders span from 1 to 31 within this interval

    • @NeetCodeIO
      @NeetCodeIO  Місяць тому +175

      Damn, it makes you realize how much thought the original programmers put into making things elegant. And then we ended up with JS, web apis, and frontend frameworks...

    • @ismbks
      @ismbks Місяць тому +6

      i wonder how many more ascii tricks there are, it's not very well documented, or just hard to find

    • @HtotheG
      @HtotheG Місяць тому +69

      @@ismbksMy favorite Ascii Hack is that each capital letter A-Z (65-90) is exactly 32 away from their lowercase counterparts (97-122) in such a way that the only difference is the 6th bit (2^(6-1) = 32) making things like case-insensitive comparisons or conversions to upper or lowercase SUPER fast bitwise operations ignoring, unsetting, or setting the 6th bit respectively.

    • @ismbks
      @ismbks Місяць тому

      @@HtotheG hell yeah.. i already knew about this one but it's a really cool hack people should definitely know! apparently cloudflare uses this for fast string filtering so it must be good..

    • @hellowill
      @hellowill Місяць тому +19

      ​@NeetCodeIO back then programmers were genius. Like you basically needed a phd, or some deep understanding of math.
      The bar has really lowered. Which I guess was necessary to scale.

  • @TestTost-j4d
    @TestTost-j4d Місяць тому +41

    To preface, You very nicely explained everything. Even the tricky bits :).
    Stack is handled by the cpu under the direction of the OS. There is still overhead when you cross the page boundary. The heap is not handled by the OS, but by the whatever allocator you use (the allocator mmap()s pages when needed). Allocators usually use "bins/buckets" for various sizes of allocations, so it's pretty fast. Unless the allocator has to mmap() some more memory.
    Anyway, what i'm trying to say is that it's complicated. Like if your language would let you, you could even use the stack as a dynamic array. Or you could mmap() a big piece of memory and just use it as a dynamic array, as memory doesn't get allocated until you touch it. Getting the same result as the stack. If the array size is fixed, the compiler could even just reserve a piece of memory from when the program is loaded (like they do for const strings).
    Cache locality is also a bit.. Cpu's cache memory in "cache lines", that are usually 64 bytes. And yea, if your resize moves the data then all those cache lines get useless. Then again the memcpy puts the new data into cache, so it's not ~that~ bad. Just that something else will get thrown out. And there's more levels of cache, like L1 is closest to the core but way smaller then L3, ofc.
    And yea, the cpu "prefetch"-es data as you read it in. It even figures out the direction, so going 0..n is the same as n..0.
    In short you always want to use as little memory as possible, and keep the memory that is accessed at the same time as close together as you can. If you can keep it in registers, like the bitfield solution, then your golden. And you ~might~ want to align/pad to some power of 2 (especially to 16 bytes for SIMD, that you even had to on older cpus).
    PS Oh, and your solution to subtract 'a' would also be faster then modulo (Modulo is divide, ofc subtract would be faster. Bdw bitwise operations usually take 1/3 of a cpu tick, the fastest operations there are (except maybe mov between registers)).

    • @egor.okhterov
      @egor.okhterov Місяць тому +4

      This ☝️
      It is not about stack or heap.
      These are just simple introductory concepts taught in University, but the majority of the people stop at that and never actually understand how memory works.
      There is MMU, TLB inside of CPU.
      There are virtual pages of 4kb that are loaded via page faults.
      There is .text, .data and .bss section which are neither heap nor stack, but are still loaded into programs address space.

    • @treelibrarian7618
      @treelibrarian7618 Місяць тому +4

      ... although modulo (%) 32 is optimized to and (&) 0x1f so is basically the same, and other static modulo's are normally optimized to 2x multiply so not so bad. and bitwise ops aren't 1/3 of a clock, they take a whole one: they just have 3 or 4 alu's that can do them so 3 or 4 can be done each tick if nothing else is happening. also, since icelake the move elimination you refer to has been removed on intel (sadge...) so mov takes same time as other ALU ops now... but zen still does it.

    • @dorianligthart3378
      @dorianligthart3378 Місяць тому

      @egor.okhterov I'd assume the devs in the video made the testing string variadic from stdin or a file (so there would be no .text section with the test string) cause otherwise the compiler, after linking, could just optimise the answer, maybe even fill it in😂 making the testing times invalid.
      What would otherwise be the point of the problem if not automation? You would write the first solution you'd come up with and wait a bit, thinking about how the younger you would waste time optimising the code hahaha
      But it's nice to finally find/read a more technical yt comment thread.

    • @saharshbhansali250
      @saharshbhansali250 Місяць тому

      I really wish I could share UA-cam comments.

  • @SanjayB-vy4gx
    @SanjayB-vy4gx Місяць тому +121

    Bro gave 2hrs length content for him

  • @dekumidoriya-qi2is
    @dekumidoriya-qi2is Місяць тому +380

    this little youtuber 🤣🤣

  • @howto.3411
    @howto.3411 Місяць тому +15

    That is a BRILLIANT video,loved watching it.

    • @NeetCodeIO
      @NeetCodeIO  Місяць тому +11

      I'm honestly glad there are people out there that enjoy this stuff as much as I do. Love deep technical concepts.

  • @juanmacias5922
    @juanmacias5922 Місяць тому +11

    These random topic videos have been really insightful, great content!

  • @GuRuGeorge03
    @GuRuGeorge03 Місяць тому +2

    I am a lead web developer and have never done any leetcode except in university. I recently started leetcode to get into a big name company that pays like 10%-20% more than my current company and videos like this are very eye opening!

    • @marcsh_dev
      @marcsh_dev Місяць тому +1

      Thats quite a bit less than I wouldve thought though. If you like the folks you work with a lot, dont get a new job for anything under 25% more than what you make now
      Being on a horrid team is the worst. Id much rather work for less money than folks I dislike.

  • @eblocha
    @eblocha Місяць тому +14

    I think you can still get a cache locality boost using an array, because the array’s memory is next to other stack variables. That means the array’s memory is more likely to be in the same cache line as the other stack variables.

    • @vasiliigulevich9202
      @vasiliigulevich9202 Місяць тому

      You only need two pointers referencing input, what array?

    • @TanmayPatil37
      @TanmayPatil37 Місяць тому

      Pointers are pointing to underlying array which has to be accessed (through the pointers)

  • @akialter
    @akialter Місяць тому +11

    What I like about your explanation is you dont “assume” the audience know a thing, you drove into the tiniest detail like what even is an AND operation. Whereas college professor always have that assumption, like oh you guys must already know about stack, heap, memory allocation, let me talk about this scheduling algorithm,…

    • @rdubb77
      @rdubb77 Місяць тому

      Because most professors suck and only “teach” for a paycheck

  • @MrSonny6155
    @MrSonny6155 Місяць тому +3

    Feels like Boyer-Moore, but without the pain of preprocessing bad-character/good-suffix tables. Very nice.

  • @urizen959
    @urizen959 Місяць тому +26

    0:15 "little youtuber" 😂😂

    • @ppercipio
      @ppercipio Місяць тому +1

      I had to do a double take just to make sure... 😂

    • @kondekinoe9337
      @kondekinoe9337 29 днів тому +1

      I double checked. And still didn't believe it first and then I turned the captions on just to be sure.

  • @criptych
    @criptych Місяць тому +7

    You can create static arrays in Python with the "array" module. Still not sure if that qualifies it as a "real" language, though.

  • @MrHaggyy
    @MrHaggyy Місяць тому

    Async or parallel optimization is also really interesting from a data structure perspective. As a chunk of cash has a specific size, we do want a structure that uses as much of a chunk as the algorithm can handle.
    This means in a forward sliding window approach we can assign each thread with a starting position and collect the results. Likewise you can often use multithreading to make a O(N^2) into a O(N × (N/threads) ). Which leads to great improvements on specific hardware.
    But it's hardware specific. Currently i'm working with a controller that only has one RAM but SIMD and MIMD. In that case you would either do the backward sliding window on the CPU, or try to fit the whole algorithm in the MIMD and do a forward brute force.

  • @DavidM_603
    @DavidM_603 Місяць тому +5

    9:50 another bit of overhead that could've been avoided at that step is reusing and clearing one vec, instead of harassing the allocator for a new one every 14 bytes lol

  • @TheOnlyJura
    @TheOnlyJura Місяць тому +4

    "the actual runtime is what matters" - tell that to the average react developer

    • @0x0michael
      @0x0michael Місяць тому +4

      Lol lol lol, they're too bothered about elgant abstraction while their apps keep making people replace their phones every two years

  • @maaikevreugdemaker9210
    @maaikevreugdemaker9210 Місяць тому +19

    I died at "we talked a bit about memory" 😂

  • @theairaccumulator7144
    @theairaccumulator7144 Місяць тому +2

    CPUs know how to add numbers together even floats though. ALUs and FPUs make it so the difference between a right shift and a multiply by 2 isn't a thing anymore.

  • @acters124
    @acters124 Місяць тому +1

    I enjoyed this. i like the mention of bit mask. using a 32 bit sized buffer, it is just so much faster to deal with bits as an index. This is assuming only lowercase(or only uppercase) Latin characters. (26 letters)

  • @thargor2k
    @thargor2k Місяць тому +2

    Maybe I misunderstood what you wanted to say in the beginning, but CPUs are totally able to add two numbers together.
    Does that in the end boil down to binary operations? Yes. But except in some very esoteric CPUs it doesn't run those binary operations, but there is dedicated circuitry to do the addition, in many cases in 1 cycle (e.g. on x86 it's a single uop, as well as on most embedded CPUs)

  • @WiseWeeabo
    @WiseWeeabo Місяць тому +3

    I feel like a lot of these optimizations actually imply knowledge of the data and is biased towards a hypothetical success or failure case.. but if you know your data, there's a whole world of N possibilities to optimize for a specific use-case..

    • @MrHaggyy
      @MrHaggyy Місяць тому

      They do imply knowledge. But quite broad knowledge is usually more than enough. For example in Bitmasking, the letter "A" is encoded in 0x65 in ASCII or 0x41 in UTF-8. We don't need to know the specific value, the information that its one byte per char and we can check for equal or not is already sufficient. Going into SIMD instructions forces you to know that 32bit = 4x8bit so you can check 4 chars in one go.
      A good optimisation is usually something really really trivial. You might want to look up how DFT or the the inverse Fourier Transform works. That one simple binary trick enabled a shit ton of things with image compression, nuclear detection or GPS beeing only a view applications.

  • @zangdaarrmortpartout
    @zangdaarrmortpartout 19 днів тому

    At 14:20 he is relocating the array every-time the windows change but with a well constructed loop it is possible to reuse the same array and toss out the indexes we know can't have been updated and contain values from the previous sub-string. On C# doing this makes this algo 4x faster.

  • @jacksong8748
    @jacksong8748 Місяць тому +2

    25:11 actually you'd see the p's but who's counting? xD
    In any case, the reverse iteration to guarantee taking the maximum step size every time was definitely the coolest optimization in my book. The second the Primeagen pointed it out it was like HOLD UP, that's so freakin clever. very cool stuff. Not often do i see an optimization that makes me "teehee" like that.

  • @yellingintothewind
    @yellingintothewind Місяць тому

    Cache locality does matter even in small arrays vs vectors. Vectors have more space overhead, as they need to track their size, current location, allocated capacity, and so on. They also cannot be packed with whatever other data is in the current stack frame. So it is harder to get the entire working set to fit in the L1 cache, or even if it nominally fits, it's more likely to have parts of it evicted and have to fetch it from the L2 cache when task switching happens in multitasking operating systems. Taken to the extreme, you have programs like CPUBurn which fit the entire program into just the main CPU registers and stress test the CPU by cycling as fast as possible, never reaching out even to CPU cache.
    Your point applies more to cache lines, which is where moving data from system memory to the L3 cache happens to bring in the _next_ data you need. The concept is related, but not what matters here.

  • @sideone3581
    @sideone3581 Місяць тому

    I am Fan of Prime but you cleared the stuff easily, He is too good and sometimes forget we don't understand his language

  • @0x0michael
    @0x0michael Місяць тому

    You're right about cache locality not being involved. It's the same thing with strings and small string optimizations

  • @kiratornator
    @kiratornator Місяць тому

    the right to left approach is often a good idea when looking for largest sub array

  • @spicybaguette7706
    @spicybaguette7706 Місяць тому

    14:00 I think the biggest is allocation, since it has to make a call to malloc every single iteration of the loop, which means one for almost every characters. I'm guessing that if you were to move the Vec::with_capacity out of the loop and vec.clear() it every time you checked a window, you would get much closer to the performance of the array code

  • @kushagrasaxena5202
    @kushagrasaxena5202 Місяць тому +28

    25:56 brother you are the "super leetcode monkey"

  • @infiniteloop5449
    @infiniteloop5449 Місяць тому +4

    This screenshot reminds of Paolo Costa’s Secret Juice ad.

  • @yes5421
    @yes5421 Місяць тому

    Just started my cs degree but I love every part of this and can’t wait to get to this level

  • @realfranser
    @realfranser Місяць тому

    You can assign each character to a prime number, you keep multiplying the result with the next number if the division has modulo different than 0 😮.
    Mem = int32

  • @pramodpotdar5416
    @pramodpotdar5416 Місяць тому

    Okay this is one of the great video I have seen in a while.

  • @valentinrafael9201
    @valentinrafael9201 Місяць тому

    Ignoring the constant *when you are learning Big O* is important, so that you dont get distracted, however, when building something, it’s only relevant if you are already at the “simplest form” or smallest big O you can achieve, and then the constant matters.

  • @lu3tz
    @lu3tz Місяць тому +1

    I stumbled across a super nice run-time optimization video in F#, it's called "F# for Performance-Critical Code, by Matthew Crews" neat stuff in there!

  • @Lifeofbhadauria
    @Lifeofbhadauria Місяць тому

    This was a great video 👏👏, enjoyed watching it, I wish youtube suggests me more videos of this type 😅

  • @BigBrainHacks
    @BigBrainHacks 18 днів тому

    Thanks for your nice and insightful explanation!

  • @sanchitwadehra
    @sanchitwadehra Місяць тому +12

    Dhanyavad bhai

  • @mulllhausen
    @mulllhausen 28 днів тому

    Once you get down to this level just write it in assembly. It's quite fun and simple

  • @zangdaarrmortpartout
    @zangdaarrmortpartout 16 днів тому

    We did it in C# and while it is difficult to understand while simply watching the video it becomes trivial simple once you start putting it on paper. We weren't able to reproduce completely the flow Prime has in Rust, I see he first add last, then check, then only remove left, which means he enters the loop with potentially 13 bits set, we did initialize a first windows covering 14 characters and then as long as 14 bits aren't set we exclude left, include right, then check. I don't think it changes a lot but I'm curious to make the code even smaller than what it currently is.
    On the next step, which is understanding how I can parallelize this, right now I don't see how.

  • @porky1118
    @porky1118 Місяць тому

    20:20 I often store stuff as bitset. It's more comfortable than working with arrays IMO.
    Recently I also turned some struct of boolean flags into a bitset. (Or I rather told some AI to do it for me, since it's pretty repetitive)

  • @devchaudhary78
    @devchaudhary78 Місяць тому +4

    ‘Prim-ye-jun’ that made me laugh harder

  • @porky1118
    @porky1118 Місяць тому

    17:30 I also always subtract 'a' instead of modding sizeof(T).

  • @TheRageCommenter
    @TheRageCommenter 5 днів тому

    Neetcode: *walks into a room*
    Inefficient algorithm: Why do I hear boss music?

  • @abdullahsaid4765
    @abdullahsaid4765 Місяць тому

    I love your explaining for hard thing video in simple english. keep going u are doing good thing.👌

  • @sainayan
    @sainayan Місяць тому +2

    Yeah, I just started learning DSA, and I see this. Wow, I'm cooked.

  • @Sanmayce
    @Sanmayce 18 днів тому

    No one mentions the work of previous coders, giving due credits is a sign of not being a talking galfon. The skipping "optimization" is Boyer-Moore.

  • @DamianL-o4e
    @DamianL-o4e Місяць тому +2

    "This little amoeba youtuber" -> Next Video, "This electron youtuber"

  • @HyperCodec
    @HyperCodec День тому

    Was not expecting to see python in the thumbnail of a video with a title containing “faster”

  • @vasiliigulevich9202
    @vasiliigulevich9202 Місяць тому

    Fixed window width is crazy. Why not track start and end separately? There would be no nested iterations, no tracking of multiple symbols.

  • @JuliaC-mz8qy
    @JuliaC-mz8qy Місяць тому +4

    no offense at all neetcode, I love neetcode. But I had a ratatouille moment when he started going into a sliding window explanation. I think im traumatized from my last job search.

  • @porky1118
    @porky1118 Місяць тому

    24:20 I started to hate if-let. In this case I'd use let-else, especially because the else case of let-else has to return (or continue/break) anyway.

  • @kushagrasaxena5202
    @kushagrasaxena5202 Місяць тому +6

    Primy-agen

  • @jonphelan707
    @jonphelan707 Місяць тому

    In a code where the loops...spin and grow
    BigO whispers...how fast can we go
    With n squared in sight...We’ll optimize all right
    And watch as that CPU blazes with new mojo!

  • @mahmoudmousa2405
    @mahmoudmousa2405 Місяць тому

    27:00 I agree the intuition made so much more sense to me

  • @CaptTerrific
    @CaptTerrific Місяць тому

    17:15 mod functions are far more expensive in terms of clock cycles than subtraction, that feels like it'd matter a lot if we're in the realm of 1,000,000% optimizations

    • @aaaabbbbbcccccc
      @aaaabbbbbcccccc Місяць тому

      %32 will get burned out by the compiler. If it wasn't a power of 2 then yes, it'd be vastly slower than the character - "a" approach

  • @spookimiiki5891
    @spookimiiki5891 Місяць тому +3

    the name is primagoon

  • @r9999t
    @r9999t Місяць тому

    This is just a tweak to Boyer Moore algorithm from 1977, which is also a tweak to the KMP algorithm from 1970. This is all very, very old news. Good algorithms to be sure, but you should have heard about them back in college, not be learning about (and seemingly shocked by) them today. Next week are we going to "discover" the B* tree? BTW, for anyone who wants to read some great tutorials on how to improve code performance, see Bentley's "Writing Efficient Programs". Also Michael Abrash has several books where he discusses code optimization (some are graphics focused, but a lot of the techniques will apply to any code). One more good reference is Hacker's Delight, but it's very low level and tough sledding if you aren't fairly advanced.

  • @ferdynandkiepski5026
    @ferdynandkiepski5026 Місяць тому +6

    The use of the modulo is a bad practice. While here we are doing modulo of a power of two on unsigned ints, which any sane compiler should optimize into an and (or do some wizardry to make it work on signed numbers as well), if these two conditions weren't met, and an actual division was performed to find the modulo, there would be a significant runtime cost. As such, your proposed method of substraction would be faster.

    • @mage3690
      @mage3690 Місяць тому +4

      So long as it's a compile-time constant, I'm fairly certain you can mod whatever number you want and it'll come out as a series of shift, sub and imul instructions. Godbolt helpfully told me that `int mod (int a) { return a % 3; }` contains not a single idiv instruction, _at zero optimizations._ At -O3, the function length went from 20 to 11 instructions. Using the 32 bit FNV_prime as the compile-time constant merely changed the constants in Godbolt's output, no other effect (ok, an lea with a multiply in the second operand got changed to an imul, whatever).
      Now, what it _absolutely will not do_ is take an array of anything, deduce that they are all _absolutely_ compile-time constants, and perform the same optimizations for each index of that array. No, for that to work, you have to declare an array of function pointers, which the compiler will refuse to inline under any circumstances (I shouldn't be surprised by that, but I sort of am).
      And apparently that optimization is just barely worth it on some CPUs: `int mod (int a) { return a % 7 }` removes the idiv on the general case CPU, but generates 14 lines of Assembly -- unless you specify `-march=znver3`, in which case the idiv comes right back, as I'm assuming it would for most modern architectures.
      Matter of fact, whatever algorithm they're using seems to get worse the further away you are from a power of 2, where the "nearest" power of 2 is always smaller than the constant. Maybe the guy who came up with the algorithm will generalize it to calculate down from the next higher power of 2 as well, and this piece of advice will become consigned to the dustbin of history. Who knows. Fascinating stuff, either way

    • @PennyEvolus
      @PennyEvolus Місяць тому +1

      Omg my brain was like wha whahuh huùuh ohhhh yeah i get it u sent me on a roller coaster ride bro

    • @PennyEvolus
      @PennyEvolus Місяць тому

      ​@@mage3690can i get that in a tldr pls im dyslexic (please ik us programmers need to read but i long for recognition and programming is the only unique skill i could learn at school to get recognition)

  • @platonvin1022
    @platonvin1022 27 днів тому

    reality is that bruteforcing on gpu is going to be faster for any reasonable size

  • @prajwals8203
    @prajwals8203 Місяць тому +1

    Would love to see more reactions vids like this lol

  • @lysendertrades
    @lysendertrades Місяць тому +1

    The name is the prime agen!

  • @EnergyCourtier
    @EnergyCourtier Місяць тому

    Love these videos. Thanks.

  • @zS39SBT4fe5Zp8Q
    @zS39SBT4fe5Zp8Q Місяць тому

    Now do it in CUDA and actually get O(1) by testing all positions in one cycle.

    • @aaaabbbbbcccccc
      @aaaabbbbbcccccc Місяць тому

      And when the number of positions exceeds your cores, what then? It isn't O(1), it's still O(n)

  • @ProfessorThock
    @ProfessorThock Місяць тому +1

    Amazing video

  • @af5772
    @af5772 Місяць тому

    hey, had to stop watching the video halfway through so maybe I missed something, but Im mainly referring to the beginning section of the video where you explain different ways to tackle the problem. When you mention dynamic array are you talking about some sort of higher level data structure that I am not familiar with? Just asking because when I hear dynamic array im thinking of a heap allocated array in C which you manipulate fully on your own with malloc and such. I mallocing some size any slower than just going for a static (stack) array. just to be clear arr[4] vs arr* = malloc(...

    • @NeetCodeIO
      @NeetCodeIO  Місяць тому +3

      dynamic array is basically a vector in cpp or a arraylist in java. js and python only use dynamic arrays. i guess another word for it would be a 'resizable array'

  • @dhruvsolanki4473
    @dhruvsolanki4473 7 днів тому

    Amazing 🎉❤

  • @Dom-zy1qy
    @Dom-zy1qy Місяць тому

    Bro this thumbnail is devious

  • @xenopholis47
    @xenopholis47 Місяць тому

    Can anybody explain why we use both binary/ 2 bit and also we use 8bit? I am noob. I am asking about the fundamental thing. Any long form answer will be appreciated.
    Edit: As I went further into the video, I realized this they are talking about DSA of which I have no idea. But still any easy explanations are welcome. Cheers

  • @bravesirrobin9576
    @bravesirrobin9576 Місяць тому

    What are you using for the diagrams and screencasting tools? They look swish

  • @lah30303
    @lah30303 Місяць тому +2

    21:10 what happens in the occurrence where there are 3 duplicates?

    • @GoKotlinJava
      @GoKotlinJava Місяць тому +3

      any extra duplicates will result in less than 14 bits set.
      Two duplicates will result in 12 bits set. (12 unique + 2 duplicates cancelling each other)
      Three duplicates will result in 12 bits set. (11 unique + 3 duplicates giving us 1 unique and 2 cancelled)
      You want exactly 14 bits in final result

  • @k98killer
    @k98killer Місяць тому

    ThePrimmyGen seems like a cool guy

  • @xymaryai8283
    @xymaryai8283 Місяць тому

    i'm a noob who's only just installed rustc and read only a few pages of the rust book, i have no clue why people approach this problem with a hash set instead of a table or vector

  • @drunkenmaster389
    @drunkenmaster389 Місяць тому

    "...by this little youtuber called the pree-mee-a-jen" 🤣

  • @VideoViewer33512
    @VideoViewer33512 Місяць тому +1

    Sometimes performance doesn't really matter at all, sometimes getting features shipped is even more important.

  • @BennyDeeDev
    @BennyDeeDev Місяць тому +1

    You lost me at bitmask, even though I am also named Benny 😢

  • @SnipeSniperNEW
    @SnipeSniperNEW Місяць тому

    I freaking looooooooooooooooooooooooooooooooooooooooooove these videooooooooooooooooooooooooooooooooooooooooos

  • @Akhulud
    @Akhulud Місяць тому

    its more like "making a faster algo" that "making an algo faster"

  • @zangdaarrmortpartout
    @zangdaarrmortpartout 22 дні тому

    Where can we find this problem text ?

  • @ehm-wg8pd
    @ehm-wg8pd 2 дні тому

    the name is premi agent

  • @lancemarchetti8673
    @lancemarchetti8673 Місяць тому

    The future of computing will eventually move away from algorithms

  • @vaolin1703
    @vaolin1703 Місяць тому +1

    Primi-Agen

  • @betadelphini4036
    @betadelphini4036 Місяць тому

    but what would be a vector in Python? A List?

    • @NeetCodeIO
      @NeetCodeIO  Місяць тому

      yeah, python only has dynamic arrays, not static ones i believe

  • @samarnagar9699
    @samarnagar9699 Місяць тому

    i saw what you did there in start what so should we calll you dr.n now

  • @FougaFrancois
    @FougaFrancois Місяць тому +1

    With your small understanding of Cache hierarchy and SIMD knowledge , I would not call myself an elite programmer ...

  • @thekwoka4707
    @thekwoka4707 24 дні тому

    Feels like the result he has wasn't even optimized. Why do windows when you can just do left and right markers?

  • @sarojregmi200
    @sarojregmi200 Місяць тому

    Bro roasted the preemagene

  • @morton4
    @morton4 Місяць тому

    guys how is the case where there are 3 or more of the same characters in the window? that bit will still be set to true, am i missing something?

    • @NeetCodeIO
      @NeetCodeIO  Місяць тому

      In that case we won't have 14 bits set to true tho.

  • @namesas
    @namesas Місяць тому

    Premiumgen is an OK guy

  • @LogsofaCodingNomad-ns9us
    @LogsofaCodingNomad-ns9us Місяць тому

    "Just a little UA-camr "

  • @jruch_2949
    @jruch_2949 16 днів тому

    Don’t know rust so didn’t do much for me

  • @EverAfterBreak2
    @EverAfterBreak2 Місяць тому

    21:50 what if there’s 3 repeated letters? The bit would be 1 again

    • @ericcoyotl
      @ericcoyotl Місяць тому +3

      Correct, but he stated that the only thing that matters is if there are 14 distinct characters (14 ‘1’s)
      If there’s 3 repeated letters, that bit would be 1. But there wouldn’t be enough other ‘1’ bits to total to 14

    • @EverAfterBreak2
      @EverAfterBreak2 Місяць тому

      @@ericcoyotl you’re right, thanks for the explanation

  • @nirmalgurjar8181
    @nirmalgurjar8181 Місяць тому

    informative ..
    (y)

  • @diobrandoggo7471
    @diobrandoggo7471 Місяць тому

    Apologies for judging that I thought you just talk like a superior human being with the tone but I can see it's just your accent / tone but you are humble and still Human and not AI (Evidence in 26:00). Subbed and will recommend to... I have no friends to recommend this type of stuff send help :( :( :(

  • @TehGettinq
    @TehGettinq Місяць тому

    a noob reviewing a noob reviewing some guy's stuff. we really hit rock bottom.

  • @solidsteal
    @solidsteal Місяць тому

    Oh, social media wars. Each one suk a dik

  • @tyulen-vn6qj
    @tyulen-vn6qj Місяць тому

    I love you all