I used all your videos when I was in the university studying for my Computer Sc degree. I'm working now and I just come back here to smile at how amazing of a teacher you are. Stay blessed!

This channel is a youtube hidden gem

I just love how he stops for a while after explaining something and looks at the camera like saying: "Did you understand, you fool?" :D

When you pause after a statement, it feels like I am actually physically sitting in the class and you are giving me a few seconds to grasp the information and proceeding after I have said Yes Sir! This feels so real! THANK YOU for doing this :) God bless you.

I’m from Nigeria and I watch all the ads just to As a way of saying thank you 😂❤️

Sir didn't used music, any intro didn't waste any time, straight to the point. And his way of explaining I find it simply the best. I'm currently doing his udemy DSA and I find his way of teaching and explaining so easy. Huge respect for him.

I love it when you stare into my soul after finishing an answer

For those who are New here, I would like to say that this Teacher here, have helped millions of students to learn DS and grab product based companies... A Moment of Respect...

Honestly everybody commented so accurately my feelings are exactly the same as every body in the comment section. I wish I could have got a teacher like you sir, when I was still in my college which ended the last month. Completed my graduation but this 'Time complexity' was not something which I understood for all my graduation years. But then discovering your channel and this lecture series ... make me feel blessed . Thanks a lot

7:45 for those who were lost like I was when he immediately goes into setting P = k(k+1)/2... Look up the "Gauss Addition Trick". Essentially this is a recognized addition sequence (1+2+3... etc) that is represented by that equation. He's assuming we know how he got there, or forgot to explain it.

So beautiful explained. I am preparing fir exams & interview watching your videos. A little mistake at 5:30 f(n)= (n^2 + n) /2

This teacher is far better than the IIT teachers, He has a great ability to teach complex things In very simple way.

corona epidemic came when I just begun my major😢 your tutorials are really helping me thanks sir. You are great man👌

The way he stops and look is a teacher look. Sir you nailed it...

Best teacher I had ever seen...its like u born for teaching.. keep going sir..👍👍

When I get stuck on solution. Sir : Let us analyse!!!! Me: 😇😌😌

"Let us Analyze" every time whenever sir says this, there is a curiosity in my mind. Awesome Explanation

Your channel is a hidden gem! I came from a different background and now studying computer science. I was having really hard time understanding these concepts in algorithm. Your videos just saved me. Big thumbs up! Keep bringing more videos like these. All the best to your channel. :)

Ooi that headmaster look in between the lectures! I imagined a flying duster :D. Jokes apart, this guys is a great teacher and he has raised the bar of how programming tutorials should be made.

Sir, I have seen the first person explaining this topic in so much detail with easy examples

I got a job sir. It was only possible because of your easy-to-understand explanation. I can remember from my 2nd year I actually was able to understand the concept of t.c. from these videos. Your Udemy's course on Data Structures was also crucial in building the base. Thanks for your teaching.

I am from Colombia and I enjoy your videos :D

Wow I think this is the by far one of the best videos on time complexity in code. Thank you so much for helping!

What a Teacher! What a Teaching! In order to help my son understand O(n) fully well, I was searching for some videos. I was not satisfied with any of them until I found this video [and the series of videos on O(n) to follow this]. Mighty helpful - all of the videos in this series. My son (CSE first year) very quickly understood O(n) to the hilt. Once again, I reiterate: "What a Teacher! What a Teaching!" Pranams ever.

*Key Takeaways:* - time complexity analysis is basically trying to find out *how the number of instructions/steps required changes as a function of the input size* - you do this by basically seeing how many times each instruction/step of the algorithm/code executes for each input - if there is an instruction inside a for loop, and the for loop goes from 0 to n (n being the size of your input), then the instruction gets executed n times...this is pretty straightforward - if there is a for loop nested within a for loop, and both loops go from 0 to n, then the instruction in the *nested* loop will be executed n x n times. This is because the inner loop is executed n times, and each time the inner loop is executed, the instruction in it is executed n times, so in total, that instruction is executed n by n times - if you have an outter for loop that goes from 0 to n, but the inner for loop goes from 0 to i of the outter loop, let's take a look at how many times the inner loop code gets executed for each iteration of the outer loop. During the first iteration of the outter loop, the code in the inner loop gets executed 1 time (from 0 to i, which is 1). During the second iteration of the outter loop, the code in the inner loop gets executed 2 times (from 0 to i, which is now 2). During the third iteration, the code in the inner loop gets executed 3 times (from 0 to i, which is now 3), and so on. You basically have a little triangle here, with height n, and base n. To find the area, you do (n x n / 2) I may be off by 1, but I wanted to keep the explanation simple. Thanks again for the amazing videos

Thank you so much Sir. Referred so many websites, blogs, wikis, spent hours to understand and your explanation made me get the concepts right within 10 minutes. Thank you so much Sir!!!

This guy is a legend, i can not find better person to explain this kind of topics

I'm so happy to view your courses. The way you explain make people to understand very clear. I would request you to publish the courses on entire data structures topics.

I don't know what to say or how to describe your lessons in words, but I really understand this subject at once watching your videos, without any doubts you are far more better than my professors in the university

Thank you from Yemen, best channel to explain Algorithm and DataStructure

This is NIIIIICCCEEE.... once in a while we get to find teachers who love their job and enjoy teaching like this gentleman.....

I love the way Mr.Abdul bari teaches. He makes things understandable. His courses on C++ (Udemy) prove these traits.

There are teachers and there are teachers !, you rate among the very best Sir, thanks for doing this video.

The videos are really amazing.....I'm overwhelmed

Sir the way you teach complex algorithms so easily is just remarkable thank you sir!

Thank you. Thank you. This by far the most detailed explanation I’ve come across on KZfaq. I love how you break it down on the board

Wow ! I have never seen such a wonderful explanation on Big O, ....... so far. Wish I had seen this earlier

Mera kal Abstract Algebra ka exam hai aur aaj mai Algorithms sikh raha hu. koi fikar nahi hai, atleast kuch tho samaj aaraha hai. ThankYou sir

What an amazing teacher! Greatly appreciate the clear explanations and enthusiasm!

when i have any problem,i go to this chennel to find solution of problem in depth way,thanks for giving us the best thinks ever

Exam tomorrow, 1.5x speed

Thanx alot from Turkey you should be instructor at university here dear AbdulBahri abi:)

beat DSA teacher I have ever seen. Explains concept very clearly. Thank you very much sir

One of the best tutorial for beginners and the way of explanation was simply awesome.

I got scared after he paused for few second. I thought he was gonna pick on me and I was thinking about the answer.

"Tum Jo Aaye Zindagi Mein Baat Ban Gayi DSA Mazhab, DSA Meri Zaat Ban Gayi"

I always have fear Of DSA but your lecture inspire me and try to complete all lecture .Ty so much sir 👍

You explained it much better than my university professor, thanks a lot man!

I just love how he stops for a while after explaining something- the real teacher - BEST

5:53 -->(n^2 +n)/2

I discovered this channel last month . May Allah blessed you. This channel is very useful for my education. Thanks for everything. Still keep watching

it was so , soothing,, to watch,, at 1x speed,, 1st time enjoying the deptness & deepness of an Experienced Teacher

ABDUL, HAVENT STARTED THIS VIDEO AND YET YOU're SAVING MY LIFE LOL

... I am currently a cs student, and have been struggling with this to the point of panic attacks and dropping out. Or switching majors.... You might have just saved my degree.... Thank you

Best teacher ever. Thanks a lot for creating this channel and sharing your knowlege. I wish all the best in the world to you. Thanks again for helping me learning CS.

Thank you so much sir, your videos are amazing! I understand the concept of time and space complexity very well now.

5:20 correction: (n(n+1))/2 = (n^2 + n)/2

Nsquare +n by 2 at 5:52 . However degree of polynomial remains same

Thank you. Finally, someone who can teach the things from the basics.

The Sound of this Video is So Good. Its So Smooth. Not Annoying. THats Good. And The Style of Teaching of Sir is very Nice. Thanks

You are so wonderful. Pls start teaching again

Do you think that there's an error in the third example that starts around 2:50? In the time units calculation, in my opinion, instead of 1 + 2 +3 + ... + n, there should be 1 + 2 + 3 + ... + n-1. Because when i = n, the for loop will be terminated. What do you guys think?

im reviewing for interviews and stumbled upon your videos. youre the greatest.

Clear, simple explanations, well done. Many thanks, this video is helpful in comprehending programming algorithm notation.

@ 5:27 it should be (n^2 + n)/2 and not (n^2+1)/2. Thanks for making these freely available on youtube

5:25 why it's not n* (n(n+1)/2)? why first loop's n executions not considered?

sir ur concepts are really awesome stay blessed always for sharing ur such priceless knowledge.......

it was wonderful lesson for me .although my english's bad I understand time complexity on loops with your clear explanation

for(int i=0; i

Machine gun at 4:28 , watch in 2x

Thankyou sir... I was struggling with these concepts for a long time. but now all clear... thankyou very much

Thank you so much sir for explaining it so clearly. This is so good for the beginners.....

Here's my explanation for the order of n^(1/2). So, when i=1, the program control goes inside the loop and the assignment statement (p=p+i) runs. This is the first time this statement executed. Let's keep track of i and p values. At first, when i =1, p =1. Now, move on to the second iteration. This time i=2 and p= (1+2). Now for the 3rd iteration, i=3 and p=1+2+3. Let's move on to fourth iteration. Now i=4 and p=1+2+3+4. Let's observe a pattern here. In total, we have run the assignment FOUR times till now which is exactly equal to the value of i. So when i= 10 (suppose) , the assignment statement will run 10 times. So when the value of i reaches k, the assignment will run for k times. We have to be aware that we are looking for how many times the assignment statement will run. So, that's k times. We found it but it's not as a function of n. So when i=k, p=(k(k+1))/2. It's a series formula for summing natural numbers upto k. This loop will stop when p>n. So (k^2+K)/2 > n . We solve this inequality and get k = (2n-k)^0.5. So, that's O(n^0.5).

The best time complexity for his videos is watching in 1.5x speed😌

I never skipped the ads because of the effort you put into this video. Very nicely explained with examples thank you sir.

Thank you for this video. You teach hard things in a very simple way. Your way of explaining really amazed me.

at 5:49, actually F(n) = (n^2 + n) / 2 [instead of (n^2 +1) / 2], the result is the same since we only take care of the n with biggest exponential

Sir in last program, you said i will run for k times, but actually value of p is deciding whether stmt has to be executed or not, when value of p is 6(which is greater than n) the stmt will not be executed. So if we see, i is executed for (1,2,3,4) i.e 4 times(n+1) and the statement p=p+i will execute for 3 times only. So the time complexity should be O(n).. is this correct or not?

You got it Sir. i swear you're heaven sent. thank you very much for existing

Thanks for your all hardwork & making concepts easy to understand ..

sir shouldn't the function be n(n-1)/2 because 'i' cannot have value 'n'

5:30 The value of f(n) should be (n^2 + n) / 2. and NOT (n^2 + 1)/2

Your ability to teach is unmatched

previously i was hating on this topic but now i started to love this topic😅

Thanks!

5:54 f(n) = ( (n^2) + n ) / 2 , shouldn't n be mulitpled to 1 or am I missing something ?

2 minutes in and I already feel smarter. Thanks a ton, Sir!

Great video watching all his videos wish he was my lecture from New Zealand

5:30 ,sir, you have made incorrect multiplication of f(n). It should be f(n) = (n^2 + n )/2.

I had noticed a problem in 5:54 since it is a nested loop then the inner loop should run f(n) = n((n^2 + n) /2) making O(n) = n^3

awesome, when I search on youtube and see your video, it's my top priority. and it's true, easily understood. jazakumullah khairan.

Thank you for this video and all video you create . You are helping me a lot ❤️❤️❤️

@5:50 see something?

R u watching in 2020

He looks dangerous but teaches very calmly and beautifully

You're the best. Thank you for all your videos about time Complexity. I tried to understand at College but you are superior then them!!!

Best teacher to explain data structures. No joke.

Thank you I have been stressing for 2 weeks and you have answered my prayers🙏🏽🙏🏽

7:37 for who did not understand the difference between k and n,assume n=10,then the loop runs for k times=4 times;p=1+2+3+4=10.That means k(value=4)

I enjoy your videos.Great explanation! Thank you Sir