7 years later, this is still best video available

Absolute legend. This dude has literally been more helpfull than I could ever imagine! Insane work!

One of the best explanation of A* algorithm I've ever seen, Thank you Sir and I hope you create more videos about AI

This channel with John Levine is awesome. What a great lecturer! Great channel! Thank you!

Thank you for this explanation. You have no idea how many pages and videos I had to go through before somebody explained that the heuristic indicates the estimated cost to a goal node. I had no idea why we only added the destination node's heuristic to the total (and not the other nodes' heuristics along the path), and now I know. Thanks!

The most coherent explanation of A* algorithm with an example. Thank you for saving our time and energy.

Thank you for this simple and great explanation... You're simply the best at this. Clean, clear, easy and very informative What else could someone ask for?!!!

Best A* tutorial for run-through! Others jump around (computerphile) too much, and its not easy to get a grasp of how we can run this algorithm by hand and how it actually works (abstracting away all the data structures). Thank you so much!

I am studying an introductory course in Artificial Intelligence here in Gothenburg, this short lecture made the A* very clear to me. Thank you!

Loved the video. Clear and Understandable. Thanks Professor John. Looking forward for more videos.

Thank you for providing free educational content of such high quality! The world needs more lecturers like yourself

Hello Sir, Best tutorial I have covered on A* algorithms. Clear and complete, include all explanations for f(n)=g(n)+h(n) and over-estimations of theoritical heuristics. Brilliant. Thank you so much.

This is amazing, You deserve more subscribers!!!

Thank you for this great video! Love your clear explanation and your voice!

Wow. Perfect lecture on A* search. Highly recommended!

I would like to say thanks to you. Your tutorial about A* is very exciting!

Absolutely phenomenal explanation. Thank you for this.

Great Explanation, as always. Just want to add one thing. at 9:43 When we reached node G2 with a cost of 13, we will stop the algorithm and won't go further with "E" node. Why? because it uses Priority Queue, the algorithm will stop once it finds a Goal node with a cost "less than or equal" to costs of other nodes. And it makes sense!! because once you reached G2 with a cost of 13, even if you have another node with the same cost, there's no point in checking it because it will only add to the cost.

Truly a godsend! Saved me 5 marks on my A levels 15mins before the exam. Couldn't have explained it better!

These videos are super helpful in explaining stuff I didn't get from my textbook! Thank you!

I love this man...... you rocked sir... hats off

Insanely clear explanation. Hope you add more details about completeness, optimality and complexity

the best teacher on the web

throwback 2 years ago, you helped me to pass my exam and understand this algorithm really well

You explained way better than my professor! Thank you! Now I finally understand it.

you're a most talented teacher. Thank you

I love the way you explain the algorithm... easy to understand...

Good example. Makes it so easy to understand admissibility issue.

in our country, today is teacher's day good sir. thank you for all of your clarification and examples that you've solved and happy teacher's day to you

It's a treat watching this as an introduction to what A* is. :D

Great job sir!!! You explain things very clearly and unambiguously . No need to watch any other vedio after watching this.

Your explanation is amazing. Thank you!

The best exemplification that I found until now, It`s worth watching.

Thank you so much Mr. Levin. Trust me these things did not make any sense in the first encounter with my Lecturer with due respect to him. I have just watched the first minute and i Have decided to download the tutorial. Hopefully I will find your explanations on all the search Algorithms. God bless you and I hope to understand these things before June for my exams

Best place to learn A*. U save my day!

Thank you very much for these efforts, greetings from Libya

Love from China. Clear explanation and it helps me a lot. Thank you!

very clear, very smooth, I like the teaching! thanks!

really insightful. I am learning AI and have been reading about agent searches for a while. This one is quite helpful. Can you also cover big O notations for time and space for these algorithms? it will help in analyzing in what environments it makes sense to apply them.

These videos are very educational and useful. Thank you so much!

very clear speech, awesome explanation. Thanks a lot!

Clear, patient, simple. Thank you.

THANK YOU! Greetings from Poland

Thank your work, i'm prepairing for AI test next week. Luckily I found this

Truly the best explanation of this algorithm we can find

You are the best teacher and provide the cleanest of explanations - at 5:53 the A* score for A is 17 (5 + 3 +2 + 7) instead of 20 I think?

A godsend. This is saving me in my CS Discrete Math class, thank you so much!

the lecture was dilivered in a logical and clear manner, thank you so much

Your videos are the best. Please do Greedy and other topics

This is a perfect video for understanding A* algorithm

what a clean teaching you are the best

thanks Mr john levine your explanation is excellnt

Clear and concise. But could you share any resource as to why the heuristic should underestimate the cost ?

It's a great illustration!! But can u give us a example of how to decide the estimate value from certain node to a goal node?

Thank you so much. Tutorials like these are hard to find :)

Thanxxxx John. You're the best !!!!!

Thank you for sharing 😊 it was really helpful for me.

Thank you for this, it is extremely clear.

I'm not very good in English but your explaination is very easy to listen and understand. Thank you very much!

Great Tutorial, Please also Make another tutorial on the Optimality proof of A∗

Amazing explanation, thank you so much!

Really like your video, it is really helpful!!!! Thank you!

I am serious like wow loved the lecture was soooooo interesting please keep this up you will be helping alot of ppl since most teachers dont know what they are talking about

Thank you sir for the explanation, it helped me a lot to understand the A* algorithm.

You are fantastic. Please make more videos.

One of the best teacher i ever seen

John the Goat! Thanks man!

thank you for your videos! I learnt alot

Just brilliant! Thank you so much! At 5:53 the A* score for A is 17 (5 + 3 +2 + 7) instead of 20 I think.

Short and to the point explanation. Thanks.

Good videos! Helped me a a lot, thanks!

thank you sir it was so clear and concise plz make more tutorials.

Thank you sir. Made it so much clearer

Sir you are the best!

Thank you for the clear explanation sir!

sir hat off for your cleaning teaching!

Sir, thank you for your amazing explanation

wawo you explained it very simply and quickly.

Dear Professor, this is such an amazing video, your way of explaining is just perfect, however i am doing a path planning for the navigation of a mobile robot in the environment, is A* the best technique to do that ? also, can you link me the litterature for this please ?

this tutorial is sooo slay thank you king

Great Video, thank you for explaining A*. For clarification if you find a node that has been visited, but the current path's A* score is less than the cost in the visited set, would you continue on the path and update the A* score in the visited set?

So, two points I believe worth mentioning for the General Public's information sake: 1. The Search considered here is a GRAPH Search - NOT a Tree search. John Levine generally considers all Graph Search for all Search Algorithms - at least in the Uninformed & this A* Algs, so far 2. The REASON why the Heuristic MIGHT BE LESS THAN the Actual Cost of Reaching of a Goal is Because the Basic Heuristic considered for an A* Search is a Straight Line Distance - SLD. And we a know a PATH is NOT ALWAYS a Straight Line. How much ever Better a Heuristic you introduce, you'll never get the Actual Cost of Reaching a Goal State to be less than it. The Best Heuristic will Predict the EXACT cost of reaching a Goal State (only with ZERO Path Costs of course as A* Cost = Path Cost + Heuristic Cost) Hope this helps.

Bravo! Awesome video

very nice explanation and example, indeed

Amazing explanation. thanks sir

Brilliant man you should make more videos

Best video for Heuristic algorithm!! Thank you !!

Hello Mr. John Levine and the rest of the people IN THE COMMENTS :). Mr. Levin thank you very much for your help. You give totally clear instructions!! :) My only question is this: is G node visited also? I think in A* goal state is also added in the visited list, right?

Very good explanation.. thank you

Thank you sir for this clear explanation of A* search.

Awesome video, thank you!

on point 👍🏻 super explanation thank you :)

Thank you so much for this video. I was looking for an explanation of A*, and I think your video just helped me fix my code and learn why I had to make the change. If I understood your comments, I should only visit a node if I either have not visited it before, or its A* score is lower from the path I am currently considering. And the A* score is a sum of how much it costs to get to a node plus the nodes heuristic value. Is that right?

Brilliant!! Thank you sooo much! :)

Thanks a lot! You really make it looks easier!

Very good lecture,thanks!

Thank you so much that helped a lot :)

really useful tutorial sir gonna subscribe your channel pls do more videos on ai....

Extremely helpful , thank you

Does the condition that the heuristic value of a node should be bigger than the distance to the goal, apply to the starting node as well? Or it only applies for the intermediate nodes?