Folks, these are actually very important patterns to keep in mind with respect to recursion. If you understand these then a lot of Binary Tree problems become very simple. I don't think any one else teaches patterns such as these in a separate video. Great work man!

Notes to Self :- All possible patters from *Subsequence* 1. Print All the Subsequence 2. Print all Sq which sums to K 3. Print only 1st Sq which sums to K 4. Print the count of Sq which sums to K *Note In order to understand Printing all subsequence in absolute clear way..... Just take the example which striver gave in previous video Now create a table of all the output and match it with the power set. A magic will happen and you will be totally blown away 🔥🔥🔥

After struggling here and there for 2 days on this topic, I understood it all in one go. The best thing about this man is he knows where a beginner might be stuck and thus shows how to think by doing dry runs, coding, and debugging with us.

I'm so grateful that I found this channel. Whoever is here, may be you found this channel late but don't worry whenever you find this channel your life is gonna take change into a new direction. I'm sooo soooo grateful to have this.

Thanks is not enough for this GIFT , love you Dada❤️

Striver always rocks!🔥🔥 In every video, he explains all the concepts in-depth. His teaching style is very unique. He starts from the basics and gradually moves up to advanced levels of questions, yet you never feel like you're solving an advanced-level question. That's the magic of Striver. I never believed that someone could teach such premium content on KZfaq for free. Hats off to this man! 💕🔥🙏

Make more videos or playlist on recursion and backtracking. I searched a lot and finally I get your videos. Your explanation is awesome, the way you teach us using dry run is amazing. Thanks a lot dada.❤️❤️🔥🙏

Previously, I never understand the concepts of recursion, and here it got fitted into my mind permanently.

Java code for K sum subsequence :- void f(int ind ,int a[] ,ArrayList list, int k,int sum){ if(ind==a.length){ if(k==sum){ System.out.println(list); } return ; } //take list.add(a[ind]); sum+=a[ind]; f(ind+1,a,list,k,sum); list.remove(list.size() - 1); sum-=a[ind]; f(ind+1,a,list,k,sum); }

Before watching this series, I was very poor in recursion. Never understood the concepts in depth. This series helped me to fell in love with recursion. Thanks Striver.

What a way of teaching striver. I am really loving recursion bcz of you🙏

i wish i have found this channel in my second year😓😓 it feels so damn motivated to see striver bhaiya's confidence❤️

One of the best playlist to understand recursion. Thanks a lot

nobody teaches me like that!! nobody ever explained me in that much deep.. best wishes my brother and Thank you for making this type of quality tutorial for free.

Striver your priceless contribution to the coding community will be cherished forever. This content is gold

I wanted to send you a heartfelt thank you for your tireless dedication to teaching DSA for free. Your selflessness and passion for helping students with their job interview preparation have made a significant impact on my life and countless others. I am incredibly grateful for the knowledge and confidence you have imparted to us. Thank you for everything you do!❣✨✨

Another brilliant video! The way you build concepts from the ground up is so helpful and intuitive. Thank you!

wish I could find this channel earlier. No one had ever explained recursion in such a simple manner. Thank you so much.

00:01 Printing subsequences whose sum is k 02:03 Understanding recursion in pattern generation 05:57 Understanding how recursion works in building a tree. 08:03 Recursion with pattern variations. 12:11 Using functional methods to print one answer in recursion. 14:21 Base case is crucial in recursion 18:15 Understanding recursion in a code 20:10 Understanding recursion and returning false on certain conditions 23:48 Implementing a simple structure for counting in recursion 25:41 Implementing recursion with count for subsequences 29:17 Two methods failed to find any subsequence 31:08 Understanding recursion in counting subsequences

amazing series man the depth you are teaching is truly commendable. you covered all the possible questions that can be made on this question.

UNDERSTOOD............Thank You So Much for this wonderful video...........🙏🏻🙏🏻🙏🏻🙏🏻🙏🏻🙏🏻

I used to struggle a lot with recursion while unraveling the code, but thanks to your patient guidance and clear explanations, most of the complexities are clear to me now. I truly appreciate your willingness to help and your ability to break down complex concepts into manageable steps. Your support has been invaluable in my learning journey, and I am grateful for the progress I've made under your mentorship❤

I am amazed as well as curious about how did you learn this on your own ? Great teaching👌

No other youtuber is shared... Thanks for all your super efforts for this wonderful video. Please, keep posting many such video bayya

Code for print all: 11:03 Code for print one: 17:17 Code for count: 32:38

After this, recursion feels like such a beautiful topic

printing only once technique is awesome. like i have tried to do in a contest but got wrong by not applying it in second "if" statement. superb solution sir

Great series so far on recursion.Only thing i will recomment here is to provide a time/space complexity after solving the program.

U r the one by which I am comfortable at programming right now

In count subsequence problem 23:16 we can take count variable and return count variable everywhere and also in place of l and r use count

One of the most impressive videos of you Everyone should watch it, whether beginner or experienced

one of the best dsa teachers in the world. thank you Striver for your contribution to computer science education.

To all who are learning recursion you all are so privileged that striver has taught all the patterns or ways by which a problem can be solved. When I was learning I have learned all these things by solving random recursion based Qus and lot of Tree problems. I highly recommend if you want to master recursion do lot of tree prblms.

best video on recursion finally this video gave me confidence in recursion which i never got

Absolutely Love the way you educate🔥 May god grant you continued success. Thank you for your efforts

I think there is no need to pass the vector ds as pass by reference in formal argument

The only person who could make me love and bring interest into recursion

I don't usually comment but this is just beautiful explaination

You are a legend, I don't know if you're aware how much impact you had on people like me who come from universities and colleges that fail to cover this topic

Took time to understand but finally understood after watching it many times Recursion is not easy to understand I feel it is one of the most complex concept But when it strike into your mind your brain automatically solve the question PS: To understand this video I will say first try to solve very basic recursion questions and slowly build the concept how multiple calls are made then try to watch this video several times in a month or so Only then I can say you can get this concept it will take time but you will get it

What a great video man, all my doubts and concepts of recursion have been cleared, keep up the good work.

Moving to L8, Learning a lot👍 thanks for the series

Crystal clear , got all the concepts at once💖

Great explanation with the dry run @Striver. Question: In the print all subsequences with sum=k question, can we have two base cases? if(sum==k): print(arr) return if(ind==n): return Since all the numbers in the array are positive integers, once we find a subsequence with the target sum, we can avoid traversing through the remaining integers. Since if we pick any other integer, the sum will always be >target. Instead we can just return at that point and check the not "picked" condition. Right?

Only one thing i have to say and that is Thank You.

Bhai one thing i can say for sure that i watch more than 50 videos on recursion and i dont get much.. But now i got your channel and now i Can do any recursion questions... Thanx bhai for your explanation 🙂

hey, striver thanks a lot man for making this series on recursion. I was not able to understand its concept and looking for a solution from last week but when I came across your channel. in just one day I understand the concept and solved 3 problems on leetcode. Thanks again main thanks you very much. 🙌🙌🙌🙌👏👏

Best recursion playlist on youtube history

Awesome bro. I literally was so dumb before your playlist. Now I am able to think, coorelate pattern and do questions.

AS ALWAYS U R THE BEST AT EXPLAINING THINGS🔥🔥

Hats off to you. God bless you!!!

Ive never sol ed subsequence problem tried it 1st time and you made it so simple

Hey Striver, Could you also please attach the link of the respective leetcode questions?

one of the best videos in the series, understood.

Would you please show us how to convert a loop in a recursion and vice versa? Also it would be better if you discuss about various types of recursion such as tail recursion etc.

Amazing video, really helped me understand recursion patterns in depth! thank youu

9:22 prn 🤩🤩🤩🤩 superb

If i can like this video thousands times I have done that .What an explanation..

3 patterns with the same problem which can be applied across various recursive solutions (thankyou striver 😊)

the way you write your code without any error is so awesome

Thank you striver, this is the best explanation I have ever seen , now I am able to correlate between different patterns of a recursion problem. Earlier I used to learn the logics but now I have started building them. Thanks for your efforts 🙂

This is indeed the best recursion series ❤️. Thanks bhaiya ❤️

Although videos are shorter but still the explaination and different patterns covers almost everything thanks

Just🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻 how can i express..... The level of confidence you put in my body

amazning video System.exit(0) will also work

Python code for K sum subsequence: def f(arr,i,subarray): if i == len(arr): if sum(subarray)==4: print(subarray) else: # include f(arr,i+1,subarray+[arr[i]]) # exclude f(arr,i+1,subarray) arr=[1,2,1,2] f(arr,0,[])

Recursion was never this easy... thanku raj ❤️❤️

23:05 you have to add a edge case that if(s>sum)return false; other wise it will give TLE overall very nice vedio bhaiya❤

very good explaination

Thank u bhaiya 🙌❤️ For this wonderful series on Recursion ❤️🙌

in JS: //printing sub seq whose sum is K // we will use take and not take function pick(i, a, arr) { if (i >= arr.length) { if (sumOf(a) === auxsum) console.log(a); return; } a.push(arr[i]); pick(i + 1, a, arr); a.pop(); pick(i + 1, a, arr); } function sumOf(arr) { let sum = 0; for (let index = 0; index < arr.length; index++) { sum = sum + arr[index]; } return sum; } // Driver code let arr = [1, 2, 3]; let auxsum = 3; let path = []; pick(0, path, arr);

love this video sab samgh mai aagya bhai thq

Not just a human, you're a brand that everyone would move to before anything else :-)

I can see the hard work of your

God Level Playlist on Recursion !!!!!!!!!!!!!!!!!

Could not understand pick/ non-pick logic initially and the reason for calling the same function twice. Now it's good.

Super useful, i wish i would have learned this way in my college days ❤

This is what crystal clear teaching is

Striver u are jusssst awesome , the questions which i used to take nearly hours to think , i am able to solve in minutes after watching yr series .❤

This is a life-changing video for me. Sach me maza aagya.

While performing a printS() function can we use stack data structure instead of vector Because for me it totally looks like the vector ds is just being used for push_back() and pop_back() no more. Correct me if I am wrong

Shandaar,Chamtkaar bhaiya . DSA ka koi v topic ek banda aap se samajh nahi paya toh wo kanhi se v samajh nahi paye gaa

Most fascinating thing about this it’s almost identical to a backtracking algorithm, where you have to conduct an exhaustive search to your base case/goal

This is just THE BEST. I don't have anything to add.

Very effective playlist.

maja a gaya bhaiya the way explain is awesome and once you dry run pogram then it makes cocept crystsal clear thank for this beautiful lectures..😍😍

Best backtracking playlist. Thanks a lot.

wonderful lectures thanks for your effort and interest to share your knowledge

Understood evry thing crystal clear

u r the best sir thanks a lot

thanks a lott😇😌😌

Brilliant video, amazing content and explained in the best possible way! Thanks a lot!! Please keep helping us with continued content in the A2Z DSA course. 🖖

Understood! Mark for revision

11:08 you can see charm on his face. he know it is quite rare.

thank you so much for such amazing content and teaching style ki toh baat hi na karo ek dum lit , i'm glad ki mene ye ep dekha , bahut time bachega mera :)💥

Incredible!! Brilliant Explanation!!! Thanks a lottt!

i practice for around 3 months but I don't understand from Kunal Kushwaha but you make clear all concepts

for counting sub seq: for [1,1,1] and sum = 2; this might not work for above scenario, since it prints answer as 3, but it s 2

Thankyou Striver, for this great explanation😊

we can directly write s + arr[i] in the function call, no need to add and subtract