I don't know if you know this, and this is 4 years late, but this is one of the cleanest, easiest to understand video's (conceptually-wise) for Dijkstra's. I've seen several, but this! This is the best one. :)
This is literally one of the cleanest, simplest, no-nonsense beautiful explanations of an algorithm I have ever watched on UA-cam. Amazing. To-the-point. Crisp. And so easy to understand and digest. THANK YOU.
Hi FTP My scenario is for a non-directed graph (you can go backwards and forwards on any edge), so all the nodes can indeed be reached. However, for a directed graph, some nodes may be unreachable from the given start, as you have intimated. Dijkstra's algorithm finds the shortest paths only to the nodes that can be reached from the starting node. (if there is no path to a node from the start, it's irrelevant). The loop will end when all 'reachable' vertices have been visited. By the way, Dijkstra's algorithm doesn't work if the graph edges have negative weights.
You sir are BY FAR the BEST teacher of algorithms on UA-cam or anywhere else I've seen algorithm lectures. THANK YOU FOR POSTING THIS! With your well-paced, methodical style you could probably teach anything!!!!
Seriously, I've been looking at so many pseudocodes and incomprehensible python scripts without any clear explanation on how the algorithm actually works. I salute you. This has helped me so much. I can't thank you enough.
I must commend the quality and clarity of this video: it is by far the best video I've seen on UA-cam to date on the subject of explaining Dijkstra's Algorithm. There are so many other videos that do not deal with the problem of keep a record of the shortest route sufficiently systematically enough, in my opinion. This video is systematic, showing the use of a table to perform the algorithm very clearly. Instruction of this level is not accidental; my congratulations to those involved in its production and execution. You have done the domain of Computer Science the world of good. Keep up the great work!
Appreciate this video. Watched a number of others about Dijkstra's Algorithm and couldn't understand HOW and at what stage another path is evaluated. It wasn't until I saw the graph and how we can track the changes that it somehow brought the entire algorithm into crystal clear focus. Thanks!
i used to think this "Dijkstra’s Shortest Path Algorithm" is not for me to understand :) , now i can do it even getting from sleep after watching this video , thanks a ton !!!
I'm a programming lover man who have no computer science degree. I have seen many videos but this is the best and easiest way to explain the algo... Thanks a lot.. want more
Such a clear and coherent explanation. Watched the Craig n Dave video on this previously but this is such a clearer explanation. Understand this now cheers!
This is very enlightening. I’ve come up with a similar algorithm myself that uses a simple width-first or depth-first search, but I’ve never thought of that we should first calculated the vertex with the least known distance! Thanks for sharing it.
Really appreciate this video. As a network engineer, i have read many book about how SPF works but this one is the best. And i can also develop the code based on this video. One thing I was stuck for a while is when having the directed graph (shorted path), it is a bit tricky to print all the shortest path considering ecmp case.
We are learning about Dijkstra's Shortest Path in my Data Communications course and this video explains the algorithm much more clearly than my professor had attempted to explain in our lecture video / notes. Thank you very much, in just 10 minutes I was able to understand something I was spending 30-60 minutes on. Well done!! :)
The best video on shortest path algorithm on UA-cam. Some of other videos that comes at the top of the search result are crap. People have unnecessarily complicated the explanation.
Fantastic explanation. Indeed, it's the best, clearest, simplest, and most useful resource by far that I've found after hours of searching. Thanks for making it!
The fact that this explanation of Dijkstra's is way more easily understandable and to-the-point than the one Computerphile has is astounding. Slides ftw
It's the clearest explaination for Dijkstra I have seen before. Here is my test code for java according to your lecture. Just a litte complicated to build the model which you present in video. import java.util.ArrayList; import java.util.List; public class Dijkstra { public static void main(String[] args){ List vertexList = buildVertexs(); // a weight or distance matrix to present vertex to other vertex if they are adjacent, // else if they are not adjacent mark as -1 int[][] matrix = new int[vertexList.size()][vertexList.size()]; matrix[0]= new int[]{0, 6, -1, 1, -1};// a-a->0,a-b->6,a-c->-1(no neighbor relation），a-d->1, a-e->-1 matrix[1]= new int[]{6,0,5,2,2};//b-a->6,b-b->0,b-c->5，b-d->2, b-e->2 matrix[2]= new int[]{-1,5,0,-1,5};// c-a->-1(no neighbor relation）,c-b->5,c-c->0，c-d->-1(no neighbor relation）,c-e->2 matrix[3]= new int[]{1,2,-1,0,1};// d-a->1,d-b->2,d-c->-1(no neighbor relation），d-d->0,d-e->1 matrix[4]= new int[]{-1,2,5,1,0};// e-a->-1(no neighbor relation）,e-b->2,e-c->5，e-d->1,e-e->0 List result =findDijkstra(matrix,vertexList); for(Vertex v: result){ System.out.println("A to "+v.getName()+" shortest path is "+v.getShortPath()); } } public static List findDijkstra(int[][] weightMatrix, List vertexList){ List visitStatus = new ArrayList(); while(visitStatus.size()!Vertex.isVisited())).min((Vertex::compareTo)).get(); int index = vertexList.indexOf(current); for(int i=0; i
I absolutely, unquestionably agree that rigorous math definition is important and necessary for this kind of stuff. That said, why do most math/cs book authors are so TERRIBLE at teaching? To the point that you have to spend gold on a number of expensive books in a desperate attempt to learn one thing well. I mean, feel free to lay out the rigorous math stuff, I know that's important, but please please PLEASE also give us a decent, understandable, not-vaguely-abstract translation of that stuff. Awesome video by the way! Thanks so much.
This is by far the best video I've seen on this subject it made implementation very easy and the explanation is the best I've ever seen so thank you very much!
Slight correction: this algorithm is not greedy! Yes, it jumps to the local optimum at every step but it also goes back and updates any decision that it has already made in previous iterations. A truly greedy algorithm would just run towards the "closest" neighbour that he hasn't already visited, most probably finding himself forced to run down an stupidly costly edge. Other than that, wonderful video!
I don't know if you know this, and this is 4 years late, but this is one of the cleanest, easiest to understand video's (conceptually-wise) for Dijkstra's.
I've seen several, but this! This is the best one. :)
Great to hear! :)KD
@@ComputerScienceLessons lol, but i'm listening even now, best explanation. Keep it up
I agree fully. Best !
@@ComputerScienceLessons He's right! It was veryyy easy to understand. Thank you
stunning, clear explanation. Thank you so much!!!
FINALLY SOME CLEAR STUFF. almost crying
jaja...you made my day
Me too!!
said what i wanna say
HAHAHAHAHA
mood
This is literally one of the cleanest, simplest, no-nonsense beautiful explanations of an algorithm I have ever watched on UA-cam. Amazing. To-the-point. Crisp. And so easy to understand and digest. THANK YOU.
!!!finally a good and simple explanation
oh tears of joy...
may the gods bless you with bugless codes
"May the gods bless you with bug-less codes."
I'm going to use that a lot.
haha epic comment bro
This has to be the best explanation of Dijkstra's Shortest Path algorithm... Thanks a lot!
We won't be visiting A, again.
Me: CRIES LOUDLY
A was no fun. :) KD
🦍🦍😂😂
Wiz Khalifa's "See You Again" Plays in The Background
i laughed hard reading this
You’re hilarious
The best video on the internet explaining the Dijkstra’s algorithm, thanks a lot sir.
You're welcome :)KD
Hi FTP
My scenario is for a non-directed graph (you can go backwards and forwards on any edge), so all the nodes can indeed be reached. However, for a directed graph, some nodes may be unreachable from the given start, as you have intimated. Dijkstra's algorithm finds the shortest paths only to the nodes that can be reached from the starting node. (if there is no path to a node from the start, it's irrelevant). The loop will end when all 'reachable' vertices have been visited. By the way, Dijkstra's algorithm doesn't work if the graph edges have negative weights.
You sir are BY FAR the BEST teacher of algorithms on UA-cam or anywhere else I've seen algorithm lectures. THANK YOU FOR POSTING THIS! With your well-paced, methodical style you could probably teach anything!!!!
Seriously, I've been looking at so many pseudocodes and incomprehensible python scripts without any clear explanation on how the algorithm actually works. I salute you. This has helped me so much. I can't thank you enough.
Yo are most welcome :)KD
Extremely clear, extremely well put together visually. Well done, and thank you.
I really appreciate your comment. Thanks.
extremely
I must commend the quality and clarity of this video: it is by far the best video I've seen on UA-cam to date on the subject of explaining Dijkstra's Algorithm. There are so many other videos that do not deal with the problem of keep a record of the shortest route sufficiently systematically enough, in my opinion. This video is systematic, showing the use of a table to perform the algorithm very clearly. Instruction of this level is not accidental; my congratulations to those involved in its production and execution. You have done the domain of Computer Science the world of good. Keep up the great work!
Thanks for the great comment Mike.
I haven't found a better tutorial than this for understanding and computing distances using Dijkstra's algorithm. Thank you so much.
You are most welcome :)KD
I can't believe how well done this video was made. I appreciate your hard work at a visual representation of this algorithm.
Lovely, this has been the clearest explanation I've seen so far for Dijkstra's algo. Seriously, thank you so much!
Thanks for saying so. You're most welcome :)KD
The VERY clearest and well-paced explanation by far! Thanks!
You are too kind :)KD
This is by far the best video I've seen on this algorithm. It is clear and doesn't skip any steps.
Thank you :)KD
BEST explanation of Dijkstra's algorithm EVER!
Even 6 years later, this is still the best explanation ever
I wish I could upvote this more than once. It is honestly a brilliant, clear, and concise explanation
You are very kind. Thanks. :) KD
@@ComputerScienceLessons But really it's awesome video.. the best info in the least possible time.. Thank you so much from India 🥰
After spending lots of time on other videos and stuff finally, I have understood "Dijkstra’s" Thanks to this LEGEND.
You are most welcome :)KD
Thanks for your extraordinary explanation. This is literally one of the simplest explanations of an algorithm I have ever watched on UA-cam.
Thank you. You are very welcome:)KD
I signed in just to like this video.
and to comment apparently
U r loyal
I have never seen a video with such clear and step-by-step explanations. Good job here!
I appreciate the comment. Thanks. :) KD
I'm watching a bunch of your videos to review for my Algorithms exam. Thanks a bunch for making these!
Thanks for the comment. It's good to hear you're finding them useful. :)
Absolutely the best explanation. Cleared up any and all lingering questions in my mind.
Appreciate this video. Watched a number of others about Dijkstra's Algorithm and couldn't understand HOW and at what stage another path is evaluated. It wasn't until I saw the graph and how we can track the changes that it somehow brought the entire algorithm into crystal clear focus. Thanks!
You are most welcome :)KD
Fantastically clear and concise. Makes my revision an absolute dream, I can’t thank you enough. 10/10
Thank you. Delighted to help :)KD
An entire computer science degree courses embedded in this amazing channel. Thank you. Not all heroes wear a cap.
This is the best video on Dijstra's Shortest path algorithm I have viewed on UA-cam. Kudos!
This is the fourth video I had to watch. Only one that explains clearly, thanks.
i used to think this "Dijkstra’s Shortest Path Algorithm" is not for me to understand :) , now i can do it even getting from sleep after watching this video , thanks a ton !!!
Thank you!
This is the single best video explaining the algorithm on UA-cam.
This video is your shortest path to learn Dijkstra Algorithm.
🤡 :)KD
man this Dijkstra guy deserved a nobel prize for it
He was a clever chap! :)KD
I'm a programming lover man who have no computer science degree. I have seen many videos but this is the best and easiest way to explain the algo... Thanks a lot.. want more
Thanks for the comment. Plenty more on the way.
Such a clear and coherent explanation. Watched the Craig n Dave video on this previously but this is such a clearer explanation. Understand this now cheers!
Glad you found it useful. There is nevertheless some good stuff on Craig n Dave's channel :)KD
Crying in disbelief 😭😭. Finally some clear explanation. Thank youuuuu
You are very welcome. Glad to help. :) KD
If you can't explain it simply, you don't understand it well enough. Beautifully done. Thank you!
This is very enlightening. I’ve come up with a similar algorithm myself that uses a simple width-first or depth-first search, but I’ve never thought of that we should first calculated the vertex with the least known distance! Thanks for sharing it.
Don't thank me, thank this guy :)KD
en.wikipedia.org/wiki/Edsger_W._Dijkstra
I've watched a lot of videos on this algorithm and let me tell you if you're watching this you are at the right place..
and thank you so much Sir!
You are very kind. Thank you :)KD
Finally a video explaining IT stuff without nearly not understandable indian accent!
Exactly! ... :D
grow up mate
They are clever though so you can't hate em.
better to eat curry than insects and dogs
Oh look kid. That thing under this guy's butt is what fire looks like.
This 10mins video >>> 45mins video from my lecturer. LEGEND🙏
Thank you for including the psuedo-code at the end. Really helped me get an idea of how I should structure my own code!
Glad to help :)KD
After watching about 5 videos on this algorithm, yours has made it crystal clear. Thank you.
You're very welcome. :)KD
@@ComputerScienceLessons Your A* explanation is also the best I found
Perfect video! Clear examples, understandable English and ... no profanity.
Glad you liked it. Thanks for the comment. :) KD
Really appreciate this video. As a network engineer, i have read many book about how SPF works but this one is the best. And i can also develop the code based on this video. One thing I was stuck for a while is when having the directed graph (shorted path), it is a bit tricky to print all the shortest path considering ecmp case.
This explanation is by far the Best I've seen.. This is crystal clear , thank you very much!
You are very welcome, and thank you :)KD
When I was doing MCA noone explain us in such a simple way...... Now it's so easy after this video... thanks for your kind information....
You are very welcome. It's a tricky topic. :)KD
We are learning about Dijkstra's Shortest Path in my Data Communications course and this video explains the algorithm much more clearly than my professor had attempted to explain in our lecture video / notes. Thank you very much, in just 10 minutes I was able to understand something I was spending 30-60 minutes on. Well done!! :)
The best video on shortest path algorithm on UA-cam. Some of other videos that comes at the top of the search result are crap. People have unnecessarily complicated the explanation.
Thanks for the comment. Much appreciated. :)
The clearest, and most succinct, explanation of Dijkstra's algo I've seen. Thanks!
This is the best explanation of Dijkstra's algorithm I have seen!! I especially like the last summary part.
Thank you. Glad to help :)KD
Fantastic explanation. Indeed, it's the best, clearest, simplest, and most useful resource by far that I've found after hours of searching. Thanks for making it!
Thank you - and you are most welcome :)KD
You are the KING THE SAVIOUR OF ALL CS MAJORS THANK GOD YOU MADE THIS VIDEO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
You are very kind, and most welcome :)KD
The fact that this explanation of Dijkstra's is way more easily understandable and to-the-point than the one Computerphile has is astounding. Slides ftw
You're too kind. Thanks you. :)KD
@@ComputerScienceLessons I thank you, recently passed my discrete maths exam :)
Wonderfully explained. The best video i have come across so far on Djikstra's Algorithm.
Great explanation! Finally, I understood it. The table really helps to not get lost. Thank you so much!
By far the best video for explaining this algorithm! Perfect.
You know this is the best illustration and guideline for implementing it on youtube.
Thanks :) KD
This video is a definition of precise and concise explanation. Thank you very much.
It's really interesting, how sometimes one thorough example can clear up everything.
Excellent work, Clarity, and explanation at all stages. Thanks, keep up the good work
The way you explained the algorithm was just great, thanks a lot for making this video!
Tnx for the feedback :)
Computer Science can you explain bellman ford too
It's the clearest explaination for Dijkstra I have seen before. Here is my test code for java according to your lecture. Just a litte complicated to build the model which you present in video.
import java.util.ArrayList;
import java.util.List;
public class Dijkstra {
public static void main(String[] args){
List vertexList = buildVertexs();
// a weight or distance matrix to present vertex to other vertex if they are adjacent,
// else if they are not adjacent mark as -1
int[][] matrix = new int[vertexList.size()][vertexList.size()];
matrix[0]= new int[]{0, 6, -1, 1, -1};// a-a->0,a-b->6,a-c->-1(no neighbor relation），a-d->1, a-e->-1
matrix[1]= new int[]{6,0,5,2,2};//b-a->6,b-b->0,b-c->5，b-d->2, b-e->2
matrix[2]= new int[]{-1,5,0,-1,5};// c-a->-1(no neighbor relation）,c-b->5,c-c->0，c-d->-1(no neighbor relation）,c-e->2
matrix[3]= new int[]{1,2,-1,0,1};// d-a->1,d-b->2,d-c->-1(no neighbor relation），d-d->0,d-e->1
matrix[4]= new int[]{-1,2,5,1,0};// e-a->-1(no neighbor relation）,e-b->2,e-c->5，e-d->1,e-e->0
List result =findDijkstra(matrix,vertexList);
for(Vertex v: result){
System.out.println("A to "+v.getName()+" shortest path is "+v.getShortPath());
}
}
public static List findDijkstra(int[][] weightMatrix, List vertexList){
List visitStatus = new ArrayList();
while(visitStatus.size()!Vertex.isVisited())).min((Vertex::compareTo)).get();
int index = vertexList.indexOf(current);
for(int i=0; i
Glad to help
This is the best explanation for Dijkstra's shortest path. Thank you so much
You are very welcome :)KD
You explained this so incredibly clearly! It's really not that hard at all! Thank you so much!
Thank you very much! I have been trying understand this algorithm for 5 hours and I finally got it now "thanks to you"!
You're most welcome :)KD
Finally, an example that makes sense, wonderful job!
Glad to help :)KD
I FINALLY UNDERSTAND THANK YOU SO MUCH!!!!
This was the most concise and easy to follow video I've managed to find on this algorithm
You are most welcome. I usually ask my students to check their understanding by working through it with a different graph. :)KD
two hours of a boring lecture vs 10mins cool explanation. thanks mate
You're very welcome :)KD
I had to watch this video two times in order to grasp the concept. Thank you!!
You are very welcome. I get my students to check their understanding by working through the algorithm with a different graph. :)KD
I couldn’t have asked for a clearer video, thank you sir.
You're most welcome :)KD
Hi from Argentina. After watching 4 other videos I can say this is the best explained solution steps I've found so far. Thanks!!
Tnx
I absolutely, unquestionably agree that rigorous math definition is important and necessary for this kind of stuff. That said, why do most math/cs book authors are so TERRIBLE at teaching? To the point that you have to spend gold on a number of expensive books in a desperate attempt to learn one thing well. I mean, feel free to lay out the rigorous math stuff, I know that's important, but please please PLEASE also give us a decent, understandable, not-vaguely-abstract translation of that stuff.
Awesome video by the way! Thanks so much.
This is a great video. You have provided a very simple but clear explanation.
This is the single best and most simple explanation of Dijkstra's algorithm. It saved me multiple times.
Thank you so much.
Thank you for the kind comment
@@ComputerScienceLessons No need!
You've just earned yourself a new subscription champ! Great video! I love it!
Thank you and you are most welcome :)
Thanks for actually including the way to find the shortest path between the start node and a certain node, alot of tutorials leave that out
You're welcome :)KD
Best video on Dijkstra I've seen so far. Thanks for doing it with so much clarity.
Thanks for this! As others have said, this is one of the clearest explanations on youtube!
Damn such a nice tutorial. Also you're making stuffs for VB, you're like the dream channel I've been searching.
Best video on Dijkstra's by a considerable margin. Subbed.
I am just captivated by the appealing spoken English
Thank you :)KD
This video is a game changer. Understood it in one shot. Brilliant!
Thank you :)KD
I had closed the tab after watching video. Just remembered and came back to give a like. Great video
Thanks for coming back. Much appreciated. :)KD
I will recommend a Nobel prize for you for this explanation
Omg.. out of like 10 dijkstra vids i attempted to eatch this is the best
u r king of simple and clear explanation
Thank you :)KD
This is by far the best video I've seen on this subject it made implementation very easy and the explanation is the best I've ever seen so thank you very much!
you are such great story teller, to learn algorithms as a story is fantastic, please continue ...
Thanks for the lovely comment. I working on some new videos at the moment.
@@ComputerScienceLessons Go on boss
Thanks to your clear explanations, I won't be visiting this video again.
Maybe just once more before the finals.
I hope you will be visiting 'A' :)KD
Slight correction: this algorithm is not greedy! Yes, it jumps to the local optimum at every step but it also goes back and updates any decision that it has already made in previous iterations. A truly greedy algorithm would just run towards the "closest" neighbour that he hasn't already visited, most probably finding himself forced to run down an stupidly costly edge.
Other than that, wonderful video!
This is the best concise explanation I found. Thanks
You're very welcome :)KD
Extremely clear and well thought out video. Thanks for uploading!
You are very welcome. Thanks for the comment. :)KD
Thank you, Kevin. Very understandable and clear.
Most efficient video on dijkstra's algorithm out there :)
Thanks James May. This was a great episode of Top Gear
Kevin, this is a great and super clear explanation, really !
Thanks for saying so :)
So easy to follow. Best video I’ve seen on this algorithm