A few viewers have pointed out an issue where a value would be out of order in some situations. A couple of commenters, Wilson Barbosa and Yebo Qin, identified what the issue was and implemented fixes and noted them in comments below. I've included Wilson's fix in the linked code, so now it should all be working properly. Let me know if anyone notices anything else though. Thanks so much to everyone who saw this and proposed fixes! This community is clearly awesome. Also, this is why code reviews are a great idea!
@wbarbosabr2 жыл бұрын
You're welcome, John! And keep up the good work!
@YebosCut2 жыл бұрын
no probs, you ve done a great job !
@TuanBuianonymous2 жыл бұрын
@@YebosCut which case is it? please give me example
@duytuannguyen83232 жыл бұрын
@@TuanBuianonymous 15:49, line 43. There's an edge case. It's not absolutely the pivot will smaller than the left pointer.
@goldfish-bloopbloop2 жыл бұрын
@@duytuannguyen8323 thank you so much!
@ginom2192 жыл бұрын
Prepping for a coding interview in Java and I’ve gotta say, your videos are the best and easiest to follow that I’ve come across. Keep up the good work
@captainjacksparrow13282 жыл бұрын
Hey, how was interview? I hope you got a job
@PhilStein7214 ай бұрын
I agree!
@Ashu-if8ryАй бұрын
Did you get the job?
@carlostitlan Жыл бұрын
I only knew quicksort is the fastest. Now I know how it works and how to code it. I also practiced recursion. Thank you very much.
@quitchiboo2 жыл бұрын
Honestly the best tutorial on quicksort out there! I'd like to add: You don't have to use a number from the array as a pivot. You can calculate the median of the array and use that as the pivot, to queeze out even a little more performance.
@TuanBuianonymous2 жыл бұрын
how to calculate the median of the array?
@quitchiboo2 жыл бұрын
@@TuanBuianonymous Count how many numbers you have. If you have an odd number, divide by 2 and round up to get the position of the median number. If you have an even number, divide by 2. Go to the number in that position and average it with the number in the next higher position to get the median.
@thanhtungtran82492 жыл бұрын
@@quitchiboo in an unsorted array, the median could be any number, such as the highest or lowest number, so it does not make the algorithm that much better
@jondevlin4754 Жыл бұрын
Just watched two of your videos … have taught gifted grade 12 CS for years … now switching from C/C++ to Java …have just watched a couple of your videos … your communication is exemplary…so clear …
@MrDarshD2 жыл бұрын
Well explained with the array visualization and the actual code creation process. Highly appreciate your time and efforts, John! Thank you so much!
@shwimwhearz48192 жыл бұрын
Instant sub, no one breaks down theses concepts quite like you John. Glad a found this channel
@Dalcenn2 жыл бұрын
Seeing you explain this with the visuals made this so much more understandable than watching my professor do it on a chalkboard! Thank you for this explanation and the sample code. Another great video John.
@vladimirgorlin75102 жыл бұрын
It worths to mention that quicksort algoritm has in avarage O(nlog (n)) time complexity
@wiilwaal258 Жыл бұрын
I dont know how i can thank u.. It took me yrs and never understood quicksort .. With ur tutorials i understood everything clearly. Thanks man 🥰
@muhammadmuaaz37042 жыл бұрын
The explaination using the numbers was amazing bro I literally understoop every single word.
@ShermukhammadKarimov5 ай бұрын
as i found about this channel, when i search for programming related content, i pray that John made a video for that topic, and when he did, I got very happy.
@MTB_Bay_Area2 жыл бұрын
Thank you, it is helpful that you show how it is done on a text file and you are moving the numbers in the text boxes. it is good visualization of the process.
@jimwang89972 жыл бұрын
Thank you John, good job! in the second while loop, not need leftPointer < rightPointer, because the first while loop already have same code.
@UnfinishedYara2 жыл бұрын
I tried it myself and without leftPointer < rightPointer in the second loop you find that the array values are flipped, so the first one becomes the last and so on.
@ralfiasz2 жыл бұрын
Definitely the best there is. Talking about your content obviously. You’ve helped me so much I couldn’t possibly thank you enough Sir!
@codewithbug6 ай бұрын
thank you, man. this is my fourth quick sort video and none of them are doing coding part. thank you, really.
@morhakak19072 жыл бұрын
Hi John, Your explanation was crystal clear + the last tweaks - the best quick sort tutorial on youtube right now.
@RK-zg9cd2 жыл бұрын
Thank you very much, John! I tried to find out working quicksort algorythm for Java, but the only one I found out has big bug. But thanks to you I won't be dropped out of my university))
@AndrewLapteff Жыл бұрын
BEST tutor about quicksort in universe!!!
@emekaukwuoma95072 жыл бұрын
Thank you John, you have just taught me quick sort algorithm in a way that is clear and understandable. I enjoyed watching and learning from your videos.
@mindofpaul95432 жыл бұрын
Dude, You are so good at explaining these things! Thank you for making these more complicated parts of coding easier to understand for a novice like me!
@millerlou72942 жыл бұрын
This video will only 30k+ views explains the concept clearer than all other more popular videos, this guys deserves more subs!
@lindascoon46522 жыл бұрын
WOW, you have the talent of teacher. Thank you for making these videos.
@luanakimley23672 жыл бұрын
Thank you for these videos, they're the clearest I've found so far! Hope you keep making more 😄👍
@svalyavasvalyava98672 жыл бұрын
Your videos are educative and really fun to watch. Thanks for all the effort you put into the content!!! P.S. on 8:16 the rightPointer should point to the pivot element. However, your implementation was perfectly correct so this is not a big deal.
@CodingWithJohn2 жыл бұрын
Thanks! And you're right, I suppose that is off by one between the implementation and the demo there. The end result should be the same either way.
@__nitinkumar__2 жыл бұрын
Thanks for that, I was implementing and had written the logic as int right = end -1; but in the John's implementation I saw it being as int right = end; // was a little confused here.
@SatyaMantha Жыл бұрын
This is the best QuickSort Algo I have seen in KZbin
@jonathancabral81242 жыл бұрын
I was having difficulty to understand the logic behind the implementation and your explanation it’s really great. There is just one thing that I do not fully understand that is why choose a random pivot it’s better than always take the last or first element.
@kannanbalasubramani5541 Жыл бұрын
I wasn't this clear of quick sort before watching this one.. It helped a lot. thank you!
@maryamz21510 ай бұрын
First time i actually understood this algorithm. thank you
@Joshua-te1fg2 жыл бұрын
This tutorials tips like over loading and eclipse method maker gave me so much joy
@RAWRIHATEYOU12 жыл бұрын
thank you so much John! I was getting really frustrated with myself because I've watched 3 quicksort tutorials, and the last video the comments were like "if you dont get it, you dont get it." felt really defeated but now I think I understand!! im currently a software engineer in test but I'd like to prepare for my future possibly as a swe. one of the videos I watched was choosing a pivot randomly in the array which had me like 🥴but this makes a lot more sense to me! kind of reminds me of binary search.
@IsaacCode95 Жыл бұрын
great stuff! i really like your videos and the way you explain stuff!, i still had to rewatch this a second time to understand the code behind it, thank you!
@siomarapantarotto2 жыл бұрын
Thanks so much, John! I loved the way you explained QuickSort. 😍
@nobleman2704 Жыл бұрын
thanks for all, btw in jdk library when it comes to sorting, it uses DualPivotQuicksort sorting algorithm
@yaweno9555 Жыл бұрын
Very well done video on quicksort with Java. I'm impressed with John as an instructor from this first video of his I watched. John explains things in a way that is easy to digest and comprehend. I came upon this one after a demo of quicksort in a Learn Haskell video. This review helped me better understand some of that foreign syntax in Haskell. I do have to say that Haskell does the quicksort in far fewer lines than Java.
@natnal9587 Жыл бұрын
As usual, easy way to understand. I just got out of the class and our professor said it better to use the median for choosing the pivot. while choosing the pivot would it better time complexity if we do (left+right /2).
@YerushalayimShelZahv2 жыл бұрын
Big thank you for sharing and teaching. I wish you much success with your channel and hope you continue producing more content. I look forward to your videos!
@ntc33372 жыл бұрын
This is great thanks! I've 4 years working experience but I'm studying for job interviews and I always find myself having to go back and learn DS&A stuff haha
@shankar74352 ай бұрын
Another quality content on KZbin. Thanks a lot.❤❤❤
@jeffreyslominsky76562 жыл бұрын
Your teaching is brilliant John, thank you for sharing!
@XtremrulesO2 жыл бұрын
Thanks John. For me, added the following line int pivotIndex = new Random().nextInt(highIndex - lowIndex) + lowIndex; makes it less efficient.
@mockingbird3809 Жыл бұрын
This is honestly the best explanation on entire KZbin!
@kermitaner Жыл бұрын
This explanation of the quicksort algo is the best i've seen so far on YT. Maybe i try to implement it in Cobol on our mainframe next week, just for fun :- )
@ishank72392 жыл бұрын
When I watched this video for the first time, I was a bit hesitant to implement it this way. It was because of the nested "while" loops. It took some careful observation to understand that although there are inner while loops, we only go through the array once : O(n) Thanks for this clear explanation. 🙏🏽
@ikennanana Жыл бұрын
Thank you so much for this video! You've really helped me get a grapsp on the QuickSort algorithm other than my professors over here...
@abdurrouf41592 жыл бұрын
Damn. Your presentation is too smart. I really fall in love on your teaching approch. I knew how the quicksort works. But, couldn't able to make understand others properly how this sorting algorithm works. You demostrated these things nicely.
@shahdadpeykani7641 Жыл бұрын
Thank you sir, finally I could understand completely after watching 10 times 😂❤️
@namrathas5804 Жыл бұрын
Thank you so much John, your videos are really a blessing to us. Its so easy to understand bcz of the visualization you make while explaining. thanks for your effort.
@Urbaez22 Жыл бұрын
Excellent video and explanation. I just add that when facing a StackOverflowError in Java, you can adjust the -Xss parameter to the JVM when booting up, to a larger value. By default I think it's 1024KB but can be set to whatever value necessary.. Thank you for your content..
@sibrimbarcenasreales55257 ай бұрын
You are a really good master, thanks i think this could took me weeks to understand it well, but you made it so easy !
@liatsahi5 ай бұрын
Thank you for this explanation. thanks to you I understood brilliantly
@heartoutloud74982 жыл бұрын
Damn John. Im loving your videos man. You really clarify stuff which other tutors just ignore, that creates a lot of trouble. I actually would ask you if you could clarify the concept of returning. Plays a crucial role in coding and I miss the point of returning ometimes: "Does return close a program?" What is the point of returning is the return is void? " "Why do we have to return?" Thank for the great videos!
@kesarscorpio2 жыл бұрын
pointing the pointers points a pointing image in my head :D thanks for the explanation, very useful.
@sarkaholendova9080 Жыл бұрын
You have helped me get through University. I appreciate you so much! :)
@emerson30702 жыл бұрын
Needs a few re-watching lol Thanks John!
@yavuzaydn64102 жыл бұрын
The explanation was amazing. Thank you John
@jugalsingh51762 жыл бұрын
Thank you for making us learn Java clearly and understand deeply😊
@DarkLightning962 жыл бұрын
Great video, one of the best explanations of quicksort I've come across! It could've been better if at the end you compared quicksort with other sorting algorithms just to see the difference in the time it takes to sort arrays as they grow larger. Maybe you could do that in another video :)
@funkyjunky8457 ай бұрын
Yeah, that's a tutorial I was looking for!
@pejko892 жыл бұрын
I watched it last night, and I did it on my own this morning. I feel so powerful xD Although I know I could never come out with the solution on my own
@CodingWithJohn2 жыл бұрын
Awesome!
@K.K.M.DEALWIS5 ай бұрын
your explanations are amazing
@coordinator30392 жыл бұрын
I really needed this for my Pokemon practice code project
@aleksandermoskov7799 Жыл бұрын
you also have drums behind you... thats awesome
@adhamkhaled53997 ай бұрын
Wow, just amazing!! Thank you so much.
@samarthurs80002 жыл бұрын
Revisiting my engineering days at the university. Felt nostalgic after hearing the terms Pivot, Left pointer, Right Pointer, and the easy-peasy Swap method and of course the Quick sort, the fastest sorting algorithm, while its poor siblings like Bubble sort, Merge sort, Heap Sort, and so on suck big time with their efficiency. Great job John. Keep up the good work and keep inspiring the needy.
@jamess17752 жыл бұрын
did you just call merge sort inefficient??
@АртемПоляков-т3х Жыл бұрын
You're literally the best, thank you! Eagerly looking forward for new videos from you🤓
@johnnyf16242 жыл бұрын
Thank you great explanation as always. we can add a condition before swap of left and right in case they are the same to prevent additional operation if (left != right) swap (numbers, left, right). also 21:34, line 30 n 31 the swap should happen before the assignment of pivot variable. rn your pivot variable is alrdy assign to random pivotIndex, the swapping doesn't do any good.
@nehemie_n2 жыл бұрын
Clear and understandable way! Smooth and smart!
@odaia.75192 жыл бұрын
Wow that is so advanced and i understod, liked it. Thank you so much, hopfully one day would be able to create something like this after finishing my Study soon in 2 monthes
@techy07162 жыл бұрын
excellent. can you also give couple of minutes to discuss Time and Space complexity of such Algo problems in terms of big O please. I find your videos very useful and well explained along the way. Thank you.
@TheEskindir2 жыл бұрын
There are great lectures on MIT open courseware, that also cover quicksort's complexity along many others. Check them out. :)
@NinjaRunningWild2 жыл бұрын
*Excellent explanation.* Far better than my 7 books on Data Structures & Algorithms (yes, 7! I was a game programmer) including Sedgewick & Cormen’s. One thing though, _please_ consider using PasteBin or a link to a file as a source. That particular site is really finicky & picky with what it allows with what browser & doesn’t like mobile much at all.
@CodingWithJohn2 жыл бұрын
Thanks! Yeah I'm certainly not married to codepile for the sources. When I have some time I'll investigate other options.
@Jkauppa Жыл бұрын
try median bucket sort, first find median, then split to two buckets O(n) for each pass, total sub-passes like a stable quick sort, always O(n log n) operations complexity
@mabeleain3320 Жыл бұрын
Thank you so much John. Best explanation I've ever seen.
@zeuss_21222 жыл бұрын
Thanks alot. My request was answered.
@athul036 ай бұрын
8:14 The right pointer is on the left side of pivot, that means highIndex-1; then why in the program rightPointer = highIndex instead of highIndex-1
@kunalkheeva2 жыл бұрын
Thank you john, I just need more clarification on time complexity
@8acv82 жыл бұрын
The best quick sort tutorial
@narendrakumariitb2 жыл бұрын
Thank you so much John💚. What a great teacher you are 👏
@Zero-ul6vx2 жыл бұрын
Bro we need a lesson on selection sort, And another on comparision between selection and insertion sort, And lastly overall comparison between all other sorting algorithm (insertion, selection, bubble, quick, merge, heap) in terms of time, space complexity and when to use. Thanks bro
@zhihangzhou71412 жыл бұрын
Nice, didn’t fall asleep in all 24mins.
@temuryakhyoev59222 жыл бұрын
I guess i found the best teacher for Java
@samuelevans91159 ай бұрын
your videos are amazing!
@adeyinkaolurin2 жыл бұрын
Thank you John. Your explanation is very understandable...
@beksaylor2 жыл бұрын
@Coding with John, You did a great job on this tutorial. Thank you very much.
@Garrison862 жыл бұрын
Awesome explanation! really appreciate the time taken to make these videos.
@anupamjoshi60772 жыл бұрын
Thank you so very much for helping me understand the concept as well as the implementation
@anupamjoshi60772 жыл бұрын
Also can we reduce one extra swap inside the while by surrounding it with an if condition which says that left pointer is not equal to right pointer
@tpttime48973 ай бұрын
I think you should make a course for DSA if not already exist. Honestly, I would get one.
@hallosf13962 жыл бұрын
We're waitin for Heap Sort !! And thanks for your effort
@schwaccc301 Жыл бұрын
Best ever,! Thank you so much for sharing this!
@checkmate26252 жыл бұрын
Hey man, Data structures and algorithms will become an interesting topic if everyone teaches like you.👍👍
@_Anna_Nass_2 жыл бұрын
Wish I had found this channel earlier. Great explanation once again, thanks!
@InvinciRD Жыл бұрын
agreed 100%
@fredericoamigo Жыл бұрын
Thank you so much for this (and all of your other vids). You truly have an extraordinary ability to explain difficult things in an understandable and nicely communicated way. I simply love your vids! Keep up the good work!
@CodingWithJohn Жыл бұрын
Thanks for the very kind words!
@abhishekkmr5492 жыл бұрын
Your channel is true gem..
@stephanieezat-panah77506 ай бұрын
Awesome tutorial. thank you!
@codeloners68202 жыл бұрын
very understandable! you are amazing tutor! keep doing such a wonderful video!
@rasa7778 Жыл бұрын
Thank you very, very much for your videos, they are very helpful for me. You are doing a great Job. ♥♥♥
@jaecheokkim992 жыл бұрын
Very easy and clear explaination! Thank you so much.
@kiranmayiippili60582 жыл бұрын
You are too good. Wonderful explanation. Thank you tons.
@francksgenlecroyant2 жыл бұрын
You're amazing John, i am your new subscriber! I'm enjoying your content