Heaps and Heap Sort
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- Опубліковано 1 жов 2024
- A demonstration of heaps, heap sort, and a competition with merge-sort.
See here www.udiprod.co... a more detailed discussion of the properties of heap sort.
Note that the procedures mentioned in the video, "sift-down", "heapify", and "sift-up", may be named differently in different descriptions of heapsort. The implementation is the same though.
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The main advantages of heap sort are that it sorts elements in place and produces a valid partial result while the algorithm is still running. With most other algorithms you don't get any results until they're finished or nearly finished. For instance merge sort produces no results until the start of the final merge. Heap sort starts producing results right after heapify is done, albeit in reverse order.
Another advantage is that heap sort doesn't require a lot of metadata. With merge sort you must keep track of all the lists to be merged, typically using a stack. With heap sort you just need a reference to the element being sifted up or down. The sift operations use tail recursion, which means they can be done iteratively.
It's not really fair to compare heap and merge with only ten elements. Try it with about 10,000 and see how they compare.
There're an inaccuracy in your statement tho. If heap sort is producing results in reverse order, just use min heap.
"reverse order"
In a order. Not 'reverse order'. The order it produces results in may or may not be the correct 'side' of the sort. It depends on if it's told to sort ascending or descending. Even then, it can invert your choice and then return the list backwards to you when you ask for it.
I find a heap most useful specifically in pathfinding. Don't actually sort it, just maintain the heap properties when all you really need to know is what is the biggest (or in some cases smallest) out of a collection, like when selecting which node to expand next.
You don't care about how the rest of the list is sorted, as long as you van get the biggest one. You can get it in one operation, then run a sift-up one time, which will take something like square root of N operations...
@@Tasarran nah it's log n, which is way less than sqrt N
How are they gonna fit that many balls, let alone make time to sort them?
It's fun how theese child-oriented videos actually explain heap implementation better than Wikipedia article. Keep up the good work!
Well, Wikipedia isn't supposed to explain stuff for better understanding, it's supposed to just provide the information for everyone. That's why these tutorial-like videos are so important.
Who said these were for children? These are for college students man!
@The Rino im a kid, and somehow I still understand it.
@@Lauren-ub6mj look at this genius guys
Jason Zhang this is already simplified enough for kids
"Each ball is brighter than its children."
Looks like those kids need some homeschooling.
That One Random Gamer there’s a lot of corruption in the ball education system- money over mind, it’s a depressing world out there for modern balls
@@zeusrulez Yeah, many balls have been popping themselves with needles. In Memoriam of Bright Maroon-Black.
xD
@@zeusrulez this comment is too underapprechiated
I'm the one dumbass thinking this was an interracial relationships joke
Heap Sort may not be ideal when sorting is all you want to do, but this whole idea of a heap becomes invaluable when you need a data structure that allows you to always take out the smallest element quickly, but also be able to quickly modify the data in the heap in between. And often in solving some more advanced problem this is exactly what you need to do it efficiently.
Maks Rosebuster Heapsort only requires one array to be used, so it doesn't take up as much memory as mergesort. Even with an array of a million objects, heapsort only takes about a second to sort everything. (I know because I just had to write a heapsort algorithm for a university project and the I remember hearing that the professor wanted us to sort that large of an array in under 30 seconds.)
You gave an explanation of priority queue with implementation, nice
Yeah, in that implementation, it’s often called a priority queue, because you can freely insert objects, and easily look at and remove the one with highest priority (imagine a hospital waiting room, where the people with worse injuries get taken in first).
K1naku5ana3R1ka very interesting
you seriously need to get those robots a set of glasses, then again, it'd prevent them from taking over without them
but then it won't be realistic, computers can't just analyze every item simultaneously
groszak1 actually a fairly simple digital logic circuit can be made to sort/compare several (less than 10) objects at once. An entirely new set of sorting algorithms would need to be implemented to take advantage of this but I wouldn't be surprised if you could get an order of magnitude improvement in sorting speed over a lucky quicksort. The problem with doing this is that sorting isn't done very often. You may ask your computer to sort things occasionally but it's not happening 60 times a second, once for each frame/update in a video game for example so doesn't need a drastic speed up.
groszak1 computers use mostly quick sort
@@groszak1 I believe it was a joke
The robots with glasses sorting algorithm is called radix sort.
I really like your videos about sorting. They are great visualized, and it is the first time for me understanding Heap Sort and Quick Sort XD
CodenameLambda Great :) Thanks!
udiprod
Nothing to thank for, because I have to thank you ;)
So: Thank you!
As an A-Level Computer Science student, I agree CodenameLambda (HL3 confirmed?). It is a lot easier to understand an algorithm when you have a visualization of what it's doing.
"Now the tree is in an illegal state"
Ok who's been planting trees in israel
😂😂 dafuck
this is great
Other trees
KKL
Now this is genius.
It's 1AM I have school tomorrow I need to finish my homework but I'm looking at CGI robots demonstrating sorting algorithms
Large Moose
realy? cgi robots, not real ones?
Pa Pinkelman
Really*
And I meant that the little CGI characters are representative of robots. So... CGI robots.
I know what you meant... I rea ll y do.
Plot twist: the homework IS about sorting algorithms
Hey, my homework is about heap sort, so what’s the problem?
So are these little robots actually in my computer?
yes it is my dude
That's bullshit, but i believe it)
@@cyllum8627 r/wooosh
They are in your blood. They carry your oxygen.
@@guidomarrone9562 **they sort your oxygen
I would like to see a Radix sort video.
Rohan Zener kinda like sorting quarters then sorting again and again until it is sorted. idk
Rohan Zener Radix sort sorts the number by the following procedure:
First it sorts the elements based on units place
Next it sorts the elements based on tens place
And so on...
Radix rocks... but not on colored balls. Which I assume was the point.
Radix only works on integers though, so it's not going to fit the colored ball example.
You can just put numbers on the balls, can't you?
Even before the match started I knew Heap sort would lose :(
It seems like a bad sort
Spoilers, man.
It's better than bubble sort, though.
It has its uses, like when speed is not that important but memory usage is a big concern.
Heap sort is not bad; it's O(nlog(n)) just like Merge sort.
I created both algorithms to test the time it takes for each to sort a vector, and actually heapSort was actually faster than MergeSort... like twice as fast. I think that making copys of the initial vector is a heavy task and makes HeapSort better or something I don't know, but numbers are really consistent
Heap sort is still my favorite, it's just a beautiful algorithm that works perfectly when you have to sort extremely large lists.
Pigeonhole sort:
@@bitonic589pigeonhole is only good if every element is unique
@@bitonic589 imagine sorting floats with that
@@official-obama Treat the floats as integers
@@official-obamaCounting sort:
It might be more efficient for someone to design better eyes for your robots :P
this is not possible, as they are looking into the souls of the balls
That’s right, skin may be darker but the soul is blacker. (Racism humor intended, no harm intended, im sure i wasnt the only one that thought this.)
DEFCON1GAMRS yeah me too
the good Boyes go at the front,the bad Boyes go to the back
the "short sighted robot" is just an metaphor for the way the algorithms are programmed.
I love how the Merge Bot had a face like "Can I leave now?" Or "Can I have my cookie now?"
I felt sorry for the Heap Sort robot still working hard while the Merge Sort robot was just standing there. I imagine merge sort robot tapping his foot impatiently!
@@KristabelHiltonwait till you see the stooge vs bogo video 🤣😭 poor dude stood there for half an hour
I like the screens in front of their table. It makes it much easier to understand.
Bro that burger look like a noob subreddit icon
Different sorting compilations started showing up in my recommended, and I started watching them, confused on what they were, and now these have shown up. I’m not disappointed, just confused.
00:07 Intro to Heap/Heap Sort
02:37 Building the Heap in the first place (Heapify)
03:33 How is new elements added into a Heap
04:07 Heap Sort V.S Merge Sort
Excellent Work! I felt like I haven't grown up yet! lol
Thank you, Yuyuko-sama
I have no idea what brought me here but this seems to be a good way to spend my quarantine
I really would like to see more of those videos about sorting. I need to find a quick way to sort my books in alphabetical order.
Quick sort could be good Take a book from the middle, and put every book that comes before that before it, and every book that comes after that after it. Repeat it with your groups, until you have groups so small, they could be sorted with a different sort.
Do smoothsort. It's along the same lines as heapsort, but does things kinda backwards so that it doesn't have to move any data if it's already sorted.
I thought h didn't exist
My teacher is now playing this in the Data Structure lesson! :)
Kinda sad though cause this is actually kind of a poor example of heap sort considering usually it's faster than merge sort
I don't know how these sorting algorithm videos could be useful to me someday..
Well, you understand how each sorting algoritm works and which one is better
If you ever get into programing
I just came from the halting problem video, amazed how great your physical world analogies are. The short-sighted robot that can only look closely at two balls at a time in order to compare them is another gem!
*takes out brightest ball*
GET DOWN ON THE GROUND
I think the robot is cute
+Deer Viehch definitely cute
Not gonna lie, this actually kinda fun to watch.
heapify: one of my new favorite words
Do gravity sort
That would be quite a show
"SORT SESAME" And then they change color
Thanks!
I Realy Struggled with Heap Sort. So This Helps ALOT.
I dont learn these in school, my main language isnt even English. But these, oh boi these are hella worth the watch
I think it would be more fair to also show a heapsort vs mergesort when the heapsort already has a heap structure. Both of these algorithms have O(n log n) time complexity, assuming the heapsort is executing on an already existing heap. Heaps have the advantage that extracting the min (or max for a maxheap) element is a consistent O(log n) time complexity, which is fantastic speed. This has a very high amount of use cases.
For a moment I lost respect for heapsort..
I think u should put numbers that represent the brightness on the ball, because numbers will help very much in illustrating as well as understanding the algorithms
i love seeing the winner robot just sit there waiting like
*can i go home now*
YES YOUR NOT DEAD!!! I KNEW IT!
I remember watching visual versions of these (the ones that make sound that sounds like if edm music made an incest baby with a 4 year old 'composing' music) and being so confused about what was going on, and your videos make things so much easier to understand. Thank you for making these, keep up the good work!
*The time complexities are*
Best: O(nlogn)
Average: O(nlogn)
Worst: O(nlogn)
Storage: O(1)
that's racist
+patsi kabelo Hahahaha!
+patsi kabelo wtf xD
One of the best, visually well explained educational videos my eyes have ever watched.
…is it weird I wish I had the money to commission this channel to animate explanations of more and more sorts in this style?
The graphics remind me of the old Kutoka Interactive edutainment games I used to play as a kid, like Mia Mouse. It feels like I’m hear to learn without judgement, and yet with little bits of humor thrown in. Not to mention all the sounds are soothing.
this video makes the concept of heapsort so obvious. honestly, i don't know why I was even wasting my time trying to decipher that thick, confusing textbook anymore.
I like that you made the ROBOT EYES MOVE, look at each ball when they are brought to the robot’s face. :)
I noticed that. :)
I found some demonstrations regarding an algorithm called "gravity sort" but I can't seem to find any video that gives an explanation. Would you be able to point me in the direction of some resources that could explain it?
The mother
The children
The children's children
The children's children's children
One major advantage to heapsort that's not addressed here. If you have more elements to sort than will fit into memory, you need to resort to an external merge sort. And the number of passes that the merge sort requires is dependent upon the number of runs (sorted sequences) that are already created. Assuming you can store N items in memory, the technique is to read in N items, sort them, then write out that run and repeat until you've created the initial set of runs. So each run is N items long. However, in heapsort, you read in N items, write out the lowest item and then read in the next item. If it's greater than the item just written, place the newly read item into the heap and continue. If it's less than the item just written, reduce the heap by 1 element and save the newly read item into storage. Result is that on average, using heapsort, the initial length of each run is 2N, not N. So you have about half as many runs to process with mergesort. So it runs faster.
Love these videos! Would be great if you could do some more. So much help. Thank you!!
This series is a gem
0:39 "now the tree is in an illegal state"
FBI OPEN UP!
The explain is so brief and clear, thanks so much.
Why am I watching adorable robots sort bowling balls by shade
great video, i enjoy the robot animations, esp the battle at the end to help actualize sorting algorithms. Helps some of us visual-programmers understand what's going on. I get sick of algorithms easily, this helps :)
Will you be doing all of the common basic/advanced sorts?
+Pyramid132420 I plan to do more of them, among other things.
The next video will be about physics again, and will be published quite soon hopefully. I promise to do another sorting video afterwards. Thanks for the suggestion. May I ask why you are particularly interested in bogosort?
udiprod I'm actually really interested in the efficiency of bogosort vs bozosort
Interesting. You don't even need a linked list or a tree to perform this sort.
always nice to see one of these
Can you do a video on gravity/bread sort? I don't understand it at all and I love your visualizations.
sakurawolfie
It just gravitates units, it can't be visualised here.
Gravity Sort just makes the darker ball heavier and vice versa and then pushes them to fall of the shelf
And bread sort just sorts bread not balls
Maybe it's for the better that you don't put your dirty little hands on gravity sort. Clearly if you need a video to understand it, it's not meant for you. Stick to bubble sort, peon.
i dont understand why anyone would need this information but its cool and i like it
can I rest now? says the yellow bot while staring...
Why did u stopped making videos. They are so good
when i first saw this sort i thought it was a variation of the selection sort. turns out it isnt
When the person says “execute”
I think of order 66 from Star Wars
It executing.
0:42 "Now the tree is *_in an illegal state."_*
-had me rolling-
I feel bad for the elements with no children
I like how they all have different tables
this ia actually useful. thanks for it.
It’s 1 am what am I doing
Heap Sort: You may (kinda) beat Quick Sort, but I will do even better then you, Merge Sort!
Merge Sort: Let's see about that!
When Merge Sort finished before Heap Sort...
Merge Sort: What's taking so long, Heap Sort!!!
Heap Sort: I don't know...
Merge Sort: Ugh, whatever, Heap Sort.
love your videos, please keep doing them :)
Thanks!
quick >= merge > heap >> bubble
4:14 im just curious if you guys make the animation faster so it does it faster, is that the case?, it doesnt look like it is faster though...
Which animation seem faster to you? They're all the same. If you ask about merge sort vs heap sort then you can check the comparisons count. They advance at a similar rate.
udiprod The yellow one, thanks for the answear
Could you please specify the decision tree which is being used in heapify? I can't figure out from how the order of which ball to look at next is being determined. And when you say the lowest ball do you mean the one at the bottom or the darkest one?
Very interesting video. I cant seem to wrap my head around the heap sorting thing but hey it was fun to try
I love these videos, but I wish youtube had recommended them to me two years ago when I was taking structure and algorithms class.... but is good to remember now, since I forgot it all
Merge sort is merging pieces
The "click here" parts in the video didn't work for me. The only thing that happened was it paused and restarted the video. Can you put links to the other videos in the description?
Done.
@@udiprod Thanks!
Oh my God that's fucking genius I realize this at like a minute and a half it just blew my mind although it could be because I'm really tired right now
I would like to see a comparison between Bubble Sort and Gnome Sort.
BTW:
When I programm something to use gnome sort, I add a variable, at which number the algorithm was, when it starts to compare to the start. Then, when it's ready, it can go just to this index and don't compare up to the turning point.
So if making a heap already organizes the list somewhat, then what’s the point in the heap? Seems rather inefficient compared to other algorithms...
“each ball is brighter than it’s children”
if you think about it it’s true in real life senses
Heap vs bubble
Through this video I understood the concept of heap sort. (I am a informatics student)
He did his best
1:01 We'll gradually move the top element downwards until it sinks down to where it belongs
"Gradually move the top element (black ball) downwards, until it sinks down to where it belongs.." What kind of racist bullshit sorting algorithm is this?
I love how these algorithims are personified as being "near-sighted". These machines aren't stupid. They don't have vision like you or me.
I feel like a chess club kid at a football practice... But the other way around... Muh Brain don't math good.
Do quick sort vs heap sort!
I just wanna see who'll win
Heap sort just has OCD and wants to make sure everything's organized while it organizes things
Can you do Selection Sort? :)
Cool
Welcome to heaps, where no one gets married.
Life must be depressing for the near sighted robots.
they have to put things inches away from their faces to see, and it takes them a while to comprehend whats infront of them, too.
you shouldgive those robots some glasses, and maybe an interpereter, too.
then they could compete much faster, and maybe the battles will be more interesting, too!
What if heapsort got a headstart by letting it heapify first?
The comparison between Heap Sort and Merge Sort isn't fair in my opinion. Merge Sort might be considered faster but at the expense of a significant increase of memory required
For visualizing heap maybe big/small-sized balls will do better than color - the bigger gets the lower
I need to see a tournament of every sorting algorithm in this style
Can we get an animation that uses numbers instead of colors?
I love all of your videos. They are the best! Keep up the good work
I can see the effort in making this video. Appreciate it. Thanks.
If the first step of the algo is to 'just pick the darkest ball', why can't it just do that and then pick the darkest ball of what is left... etc.