Graph Data Structure 4. Dijkstra’s Shortest Path Algorithm

This is the fourth in a series of computer science videos about the graph data structure. This is an explanation of Dijkstra’s algorithm for finding the shortest path between one vertex in a graph and another. Indeed, this explains how Dijkstra’s shortest path algorithm generates a set of information that includes the shortest paths from a starting vertex and every other vertex in the graph. It also mentions why Dijkstra’s shortest path algorithm is an example of a greedy algorithm.

[@daringdarius5686]

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. :)

[@ComputerScienceLessons]

Great to hear! :)KD

[@vijayalakshmi0714]

@@ComputerScienceLessons lol, but i'm listening even now, best explanation. Keep it up

[@eatbreathedatascience9593]

I agree fully. Best !

[@tudorradu5848]

@@ComputerScienceLessons He's right! It was veryyy easy to understand. Thank you

[@555aboud]

stunning, clear explanation. Thank you so much!!!

[@assansanogo1343]

FINALLY SOME CLEAR STUFF. almost crying

[@OscarSotomayor]

jaja...you made my day

[@MinecraftLetstime]

Me too!!

[@SkyWalker9669]

said what i wanna say

[@exactzero]

HAHAHAHAHA

[@veggieblues]

mood

[@SouravendraKrishnaDeb]

We won't be visiting A, again. Me: CRIES LOUDLY

[@ComputerScienceLessons]

A was no fun. :) KD

[@ashutoshthite]

🦍🦍😂😂

[@trulyharsh]

Wiz Khalifa's "See You Again" Plays in The Background

[@user-wq2iv3cq2h]

i laughed hard reading this

[@royazut550]

!!!finally a good and simple explanation oh tears of joy... may the gods bless you with bugless codes

[@neelparekh9846]

"May the gods bless you with bug-less codes." I'm going to use that a lot.

[@neptechbyte]

haha epic comment bro

[@faisalsal1]

This video is your shortest path to learn Dijkstra Algorithm.

[@ComputerScienceLessons]

🤡 :)KD

[@adityapappu4963]

This is literally one of the cleanest, simplest, no-nonsense beautiful explanations of an algorithm I have ever watched on KZbin. Amazing. To-the-point. Crisp. And so easy to understand and digest. THANK YOU.

[@reiniervanleeuwen9815]

This has to be the best explanation of Dijkstra's Shortest Path algorithm... Thanks a lot!

[@TANEM315]

You sir are BY FAR the BEST teacher of algorithms on KZbin or anywhere else I've seen algorithm lectures. THANK YOU FOR POSTING THIS! With your well-paced, methodical style you could probably teach anything!!!!

[@ComputerScienceLessons]

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.

[@matthewsattam1982]

Extremely clear, extremely well put together visually. Well done, and thank you.

[@ComputerScienceLessons]

I really appreciate your comment. Thanks.

[@trellas3689]

extremely

[@mikefriedman9573]

Absolutely the best explanation. Cleared up any and all lingering questions in my mind.

[@mikelanigan9601]

I must commend the quality and clarity of this video: it is by far the best video I've seen on KZbin 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!

[@ComputerScienceLessons]

Thanks for the great comment Mike.

[@amine_fadssi]

The best video on the internet explaining the Dijkstra’s algorithm, thanks a lot sir.

[@ComputerScienceLessons]

You're welcome :)KD

[@Jbbubanic5434]

I can't believe how well done this video was made. I appreciate your hard work at a visual representation of this algorithm.

[@hadeneh]

I signed in just to like this video.

[@magicianwizard4294]

and to comment apparently

[@hariprasathgcse3381]

U r loyal

[@johnstorm589]

Even 6 years later, this is still the best explanation ever

[@timuralmamedov1900]

Great explanation! Finally, I understood it. The table really helps to not get lost. Thank you so much!

[@SpaceDisco1]

It's really interesting, how sometimes one thorough example can clear up everything.

[@lewistian7975]

BEST explanation of Dijkstra's algorithm EVER!

[@Museko]

I'm watching a bunch of your videos to review for my Algorithms exam. Thanks a bunch for making these!

[@ComputerScienceLessons]

Thanks for the comment. It's good to hear you're finding them useful. :)

[@MimicalThought]

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!! :)

[@tundet8963]

Excellent work, Clarity, and explanation at all stages. Thanks, keep up the good work

[@taruchitgoyal3735]

I haven't found a better tutorial than this for understanding and computing distances using Dijkstra's algorithm. Thank you so much.

[@ComputerScienceLessons]

You are most welcome :)KD

[@alpharussel653]

An entire computer science degree courses embedded in this amazing channel. Thank you. Not all heroes wear a cap.

[@jacklimestone2559]

Thank you! This really helped me out with my assignment! Nice accent, clear explanation, and visually pleasing.

[@markh1791]

The clearest, and most succinct, explanation of Dijkstra's algo I've seen. Thanks!

[@Satharus]

Thank you! This is the single best video explaining the algorithm on KZbin.

[@jackych5055]

man this Dijkstra guy deserved a nobel prize for it

[@ComputerScienceLessons]

He was a clever chap! :)KD

[@aquilazyy1125]

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.

[@ComputerScienceLessons]

Don't thank me, thank this guy :)KD en.wikipedia.org/wiki/Edsger_W._Dijkstra

[@tartarus1322]

I wish I could upvote this more than once. It is honestly a brilliant, clear, and concise explanation

[@ComputerScienceLessons]

You are very kind. Thanks. :) KD

[@chinthalaadireddy2165]

@@ComputerScienceLessons But really it's awesome video.. the best info in the least possible time.. Thank you so much from India 🥰

[@ronglass5968]

The VERY clearest and well-paced explanation by far! Thanks!

[@ComputerScienceLessons]

You are too kind :)KD

[@ietskaag552]

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.

[@ComputerScienceLessons]

Yo are most welcome :)KD

[@leox8888]

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.

[@andresnieves9018]

If you can't explain it simply, you don't understand it well enough. Beautifully done. Thank you!

[@Aca99100]

I have never seen a video with such clear and step-by-step explanations. Good job here!

[@ComputerScienceLessons]

I appreciate the comment. Thanks. :) KD

[@ayasswain]

Wonderfully explained. The best video i have come across so far on Djikstra's Algorithm.

[@Moggery]

Fantastically clear and concise. Makes my revision an absolute dream, I can’t thank you enough. 10/10

[@ComputerScienceLessons]

Thank you. Delighted to help :)KD

[@Monochones87]

Lovely, this has been the clearest explanation I've seen so far for Dijkstra's algo. Seriously, thank you so much!

[@ComputerScienceLessons]

Thanks for saying so. You're most welcome :)KD

[@babakbekhradmanesh871]

Thanks for your extraordinary explanation. This is literally one of the simplest explanations of an algorithm I have ever watched on KZbin.

[@ComputerScienceLessons]

Thank you. You are very welcome:)KD

[@MinecraftLetstime]

By far the best video for explaining this algorithm! Perfect.

[@tumarisyalqun7327]

This is so far the best explanation I have seen, thank you so much!

[@JamshadAhmad]

This video is a definition of precise and concise explanation. Thank you very much.

[@supernenechi]

You explained this so incredibly clearly! It's really not that hard at all! Thank you so much!

[@lawrencedennison-hall9642]

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!

[@ComputerScienceLessons]

Glad you found it useful. There is nevertheless some good stuff on Craig n Dave's channel :)KD

[@sanseverything900]

Thank you for including the psuedo-code at the end. Really helped me get an idea of how I should structure my own code!

[@ComputerScienceLessons]

Glad to help :)KD

[@TourGuideFTW]

The way you explained the algorithm was just great, thanks a lot for making this video!

[@ComputerScienceLessons]

Tnx for the feedback :)

[@swethapuskoor7314]

Computer Science can you explain bellman ford too

[@5he1tied]

This is the fourth video I had to watch. Only one that explains clearly, thanks.

[@hgjghjkhify]

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!

[@ComputerScienceLessons]

You are most welcome :)KD

[@abooth1707]

Best explanation I've ever seen of this. Thank you so much!

[@nitesh4146]

This is the best video on Dijstra's Shortest path algorithm I have viewed on KZbin. Kudos!

[@ulfinawakjira1977]

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!

[@smith1923]

This is by far the best video I've seen on this algorithm. It is clear and doesn't skip any steps.

[@ComputerScienceLessons]

Thank you :)KD

[@javadsabbagh8939]

Thank you, Kevin. Very understandable and clear.

[@GavinLon]

This is a great video. You have provided a very simple but clear explanation.

[@selvalooks]

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 !!!

[@ammarulhassan5851]

After spending lots of time on other videos and stuff finally, I have understood "Dijkstra’s" Thanks to this LEGEND.

[@ComputerScienceLessons]

You are most welcome :)KD

[@_elguet5787]

thank you I was really struggling implementing this algorithm in real coordinates, i realized coordinates are like grid/trees if you zoom it, and i could apply your ideas and explanation to find the shortest path available in a set of xyz 'real' coordinates! awesome.

[@mdotub71]

Excellent graphical and verbal explanation, very simple and coherent. Thanks for your video.

[@amskumar]

Best video on Dijkstra I've seen so far. Thanks for doing it with so much clarity.

[@ThewOrldIssqUare]

Thanks for this! As others have said, this is one of the clearest explanations on youtube!

[@dimensionalblade2778]

Damn such a nice tutorial. Also you're making stuffs for VB, you're like the dream channel I've been searching.

[@dawnjinx4962]

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

[@ComputerScienceLessons]

You are most welcome. I usually ask my students to check their understanding by working through it with a different graph. :)KD

[@nathanriches9547]

Thanks James May. This was a great episode of Top Gear

[@DentrifixoRam88]

Hi from Argentina. After watching 4 other videos I can say this is the best explained solution steps I've found so far. Thanks!!

[@ComputerScienceLessons]

Tnx

[@user-lh2cq7yy6b]

Man this content mind-blowing clear and simple explained, great work

[@michellelopez5264]

mannnn, i've been trying to find the missing link with this stuff and your video finally shined some light on the subject!

[@ice_cube918]

This is the best explanation of Dijkstra's algorithm I have seen!! I especially like the last summary part.

[@ComputerScienceLessons]

Thank you. Glad to help :)KD

[@alejandrobonilla3201]

You are the best on explaining... Thanks a lot!

[@whiningmachine]

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!

[@ComputerScienceLessons]

Thank you - and you are most welcome :)KD

[@young-julee7899]

D E A D

[@ComputerScienceLessons]

Accidental!

[@yunyizhu8358]

kinda scary when it turns red lol

[@MarkTheMadMan]

haha i saw this instantly, maybe its a sign :/

[@celsiusfahrenheit1176]

(ʘᗩʘ')

[@iansugg3496]

Me after my Data Structures and Algorithms final exam

[@BrendonWilliams]

Best explanation I could find. Thanks.

[@ricp]

This explanation is by far the Best I've seen.. This is crystal clear , thank you very much!

[@ComputerScienceLessons]

You are very welcome, and thank you :)KD

[@sabeen7794]

great video ... you really have the spirit of a teacher ... thanks for making this one.

[@q1chen]

This 10mins video >>> 45mins video from my lecturer. LEGEND🙏

[@RubainG]

Awesome video ! This made me clear how to simplify and program the Seam algorithm!

[@nehascorpion]

Very well explained! Best video so far on this algorithm. Thanks a ton.

[@RustysAdventures]

This video is a game changer. Understood it in one shot. Brilliant!

[@ComputerScienceLessons]

Thank you :)KD

[@GANDHIXtv]

Best video on Dijkstra's by a considerable margin. Subbed.

[@chrise202]

You know this is the best illustration and guideline for implementing it on youtube.

[@ComputerScienceLessons]

Thanks :) KD

[@stuffboutthegovermet]

So easy to follow. Best video I’ve seen on this algorithm

[@Jack-hd3ov]

After watching about 5 videos on this algorithm, yours has made it crystal clear. Thank you.

[@ComputerScienceLessons]

You're very welcome. :)KD

[@Jack-hd3ov]

@@ComputerScienceLessons Your A* explanation is also the best I found

[@kexiuliu6692]

Really good show of the algorithm. thanks a lot.

[@JaffarBrar]

Crying in disbelief 😭😭. Finally some clear explanation. Thank youuuuu

[@ComputerScienceLessons]

You are very welcome. Glad to help. :) KD

[@ddddchannel837]

Extremely clear and well thought out video. Thanks for uploading!

[@ComputerScienceLessons]

You are very welcome. Thanks for the comment. :)KD

[@danielm7755]

You've just earned yourself a new subscription champ! Great video! I love it!

[@ComputerScienceLessons]

Thank you and you are most welcome :)

[@theobserver4794]

two hours of a boring lecture vs 10mins cool explanation. thanks mate

[@ComputerScienceLessons]

You're very welcome :)KD

[@drowmik]

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

[@ComputerScienceLessons]

Thanks for the comment. Plenty more on the way.

[@m_t_t_]

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

[@ComputerScienceLessons]

You're welcome :)KD

[@KevinIaMmE94]

I had to watch this video two times in order to grasp the concept. Thank you!!

[@ComputerScienceLessons]

You are very welcome. I get my students to check their understanding by working through the algorithm with a different graph. :)KD

[@chrismorris3056]

Very clear explanation. Well done!

[@ComputerScienceLessons]

Tnx Chris

[@miller5565]

I couldn’t have asked for a clearer video, thank you sir.

[@ComputerScienceLessons]

You're most welcome :)KD

[@ahmedsaid8180]

Thank you very much! I have been trying understand this algorithm for 5 hours and I finally got it now "thanks to you"!

[@ComputerScienceLessons]

You're most welcome :)KD

[@leonidsukharnikov2563]

Perfect video! Clear examples, understandable English and ... no profanity.

[@ComputerScienceLessons]

Glad you liked it. Thanks for the comment. :) KD

[@forestpfeiffer1370]

Finally, an example that makes sense, wonderful job!

[@ComputerScienceLessons]

Glad to help :)KD

[@hanbrianlee]

Omg.. out of like 10 dijkstra vids i attempted to eatch this is the best

[@lolking420]

This is the best explanation for Dijkstra's shortest path. Thank you so much

[@ComputerScienceLessons]

You are very welcome :)KD

[@covelus]

a very good explanation, thanks a lot! I haven't seen this algorithm since 12 years ago, and I don't remember anyone explaining so clearly in the University

[@ComputerScienceLessons]

Tnx

[@LeodSMW]

At 4:01 it struck me how this is going to work and how clever it is. Really neat!

[@ComputerScienceLessons]

Agreed. You have to admire Edsgar Dijkstra for dreaming it up.

[@Funnybone_FB]

Brilliant. Very well-done and clear explanation. Thank you for this!

[@ComputerScienceLessons]

Thank you. You are most welcome :)KD

[@danpang9213]

I am just captivated by the appealing spoken English

[@ComputerScienceLessons]

Thank you :)KD