Longest Subarray with sum K | Brute - Better - Optimal | Generate Subarrays

Notes/C++/Java/Python codes:
Longest Subarray with sum K [positives]: takeuforward.org/data-structu...
Longest Subarray with sum K [positives + negatives]: takeuforward.org/arrays/longe...
Problem links.
Longest Subarray with sum K [positives]: bit.ly/3GHyBOS
Longest Subarray with sum K [positives + negatives]: bit.ly/3mNSZ9u
We have solved the above problems, and we have gone from brute force and ended with the most optimal solution.
Full Course: bit.ly/tufA2ZYt
You can follow me across social media, all my handles are below:
Linkedin/Instagram/Telegram: linktr.ee/takeUforward
0:00 Introduction of course

[@takeUforward]

Let's march ahead, and create an unmatchable DSA course! ❤ Timestamps pleaseeee Use the problem links in the description.

[@vishal_s583]

Thanks for your effort ❤️

[@factsmadeiteasy9943]

Bhaiya how can I keep that check marks permanently... because it always get cleaned up 😩

[@leoved1073]

@@factsmadeiteasy9943 bro history ya cookies clear mat karo tumhari progress cookies me save hoti hai...

[@factsmadeiteasy9943]

@@leoved1073 oh thanks bro 👍🏻

[@111rhishishranjan2]

i think that this problem could be done by just using hashmap.

[@ashutoshbhardwaj1369]

I've been watching this lecture for the last two days, and it was so frustrating that I couldn't understand the concept, even though Raj Bhaiya explained it thoroughly. After putting in about 7-8 hours, I finally understood what was holding me back. Here's what I've learned: 1. map_name.find(value)-> This function returns an iterator to the element with the key `value` if it is present in the map. If the key is not found, it returns an iterator to `map_name.end()`. 2. map_name.end()-> This function returns an iterator one past the last element of the map. If your map has a size of 4 (indexing from 0 to 3), `map_name.end()` will give you an iterator representing index 4, which is beyond the last element. 3. if(map.find(value) != map.end())-> This line was a real pain in my ass so basically this line checks whether the key `value` is present in the map. If `map.find(value)` does not equal `map.end()`, it means the key is found in the map.similarly , if `map.find(value)` equals `map.end()`, the key is not present in the map. Understanding this line was crucial for me. The `.find()` function returns an iterator to the element if it is present, or `map.end()` if it is not. So, the condition `if(map.find(value) != map.end())` essentially means, "if the key `value` is found in the map." If you've read this far, all the best, buddy! I was literally crying inside after watching the video again and again, but if a noob like me can understand it, you will definitely nail it. Haha. Thanks, Raj Bhaiya. ❤

[@Srijan-ye7xw]

Proud of your efforts bud ❤ let's keep going

[@archanashah4542]

Thanku this helped a lot

[@randomtsareenalover9014]

thanks a lot bro, im on the hard section rn and was stuck on the longest zero sum problem and i found this!

[@dikshabisen504]

you stuck over the thing where map comes....i cant even get the approach ...ye longest subarray ka approach hi nhi ghus rha bhaiii

[@nirbhaybhardwaj4330]

Thanks a lot buddy!

[@viveknandan4950]

When Striver says no one will teach you in such depth, he means it

[@Awanderer15]

To all those whose mind are like " shyd coding is not for me" after seeing this question Take my one advice am the one solving it from 11 :am in the morning and understood it at 7 20 pm of evening I between my mind qas like chod de "pr bhaiya chodna hi toh nhi hai tabhi toh smjega" So give yourself a shootout and say striver bhaiya i will play you once more and play it back to back even if you have watched for 100 times play it slowly took a pen copy and try to understand what bhaiya is saying 🎉🎉

[@thevaishndra]

was literally feeling the same, but you sowed a new hope in me

[@vartikasharma2587]

thanks for this comment !!!instilled hope in me.

[@rishabhinc2936]

cringe

[@v.keerthigakeerthi428]

🥺🥺

[@DTALKS01]

i am abouve to change a someone else video but you give me hop

[@JustExploreByTravel]

I am following your playlist for DSA. I got subarray of string related problem in my JP Morgan interview. I have explained the approach as you taught. It was quite simple for me to explain the approach as I had watched your this video.. Thank you so much sir you are doing very well.

[@Wonderfully_ok]

did u get into jp morgan?

[@Piyushraj0]

TIMESTAMPS 0:00 Intro 0:43 Problem Explanation 3:37 Brute force approach 10:50 Better approach (Both positives + negatives) 26:57 Time complexity of Hashing based better solution and why its best for both positives and negatives 28:55 Optimal solution (positives only) 37:52 Time complexity of two pointer based optimal solution

[@MeiteiProgrammer]

thanks dude

[@Yseja]

Thank you bro

[@salihedneer8975]

Striver please add this so everyone wud be get useful of this

[@LeelaLakshmiKundi]

thanks bhai

[@gunslingerlynx3964]

That hashing one went above my mind maybe need to watch it again

[@DK-ox7ze]

Absolutely brilliant. Haven't seen anyone else on KZbin explaining any dsa problem with this much clarity.

[@utsavseth6573]

Please keep this series continued. Brilliant work Raj. I am speechless. An if anyone reading this, and you have a difficulty understanding, don't give up, just watch 2-3 more times, you shall understand, trust me.

[@Akash-yr2if]

LOL, I came back today and now the things are getting cleared.

[@shivvratraghuvanshi522]

​@@Akash-yr2ifyeah!!

[@barnam_das]

thats the spirits boys, lets goooooo !!!!!!!!

[@sourabhtiwari5137]

for one question , 3 hours is it a joke

[@tanya8353]

You are doing a wonderful job man!!! Really grateful to people like you who provide such quality content with such a dedication !!

[@tahaansari5621]

Had to watch it twice to understand it like 95% but did understand it. Really impressive stuff!

[@takeUforward]

It's easy if you do a dry run on yourself

[@DevashishJose]

@@takeUforward yes I was also confused but when I did the Dry run I got it.

[@crazybro4383]

Mujhe both positive and negative ka optimal samajh hi ni aaya, like approach I understood in one go and found it very easy. But code ni smjh aaya 2 baar dekhne par bhi. I also refered to striver's website but smjh hi ni aara kuch. Should I leave it for now ? (ps- I am a beginner first year student)

[@ViditPandey06]

@@crazybro4383 just keep working you will eventually understand.

[@eklavya22k34]

Those who understand the beauty of ur optimal codes, will agree, ALL UR LEC.S ARE PURE GOLD. U are a gr8 GURU .... sharing such exceptional lec.s for free is superb SERVICE FOR MANKIND. U are empowering youth ... making difficult topics look like easy .... u explain everything so easilty ... study looks like fun when u teach. Codes can revolutionise the world ... can take us to distant planets.... Codes are like miracle ... the way incredible creation like AI is developed .... Sw Er.s are next Gen soldiers of nation. They can fuel engine of growth and contribute in development of nation and growth of humanity. U r doing exceptional work ... Thank for evth..... God bless u ... Tc.

[@afzhalahmed2051]

You are helping families not individuals. Thanks for this.

[@vm1662]

Teaching is an art and you have nailed it, my friend. Another amazing one from Striver. Thank you!

[@codingaspirant9446]

You are like Virat Kholi.

[@justcode7326]

Consistent and hardworking

[@vinaykrishna747]

Yes...

[@arnab027]

Better than kohli kohli can't secure 1000 students' future but striver can.

[@helloworld2054]

Don't compare a great teacher with a choker

[@calisthenics5247]

​@@arnab027 yeah but kohli do donate money to save lives of lakhs of people and he also made our country pride a large number of times you fools

[@tanishqbansal8462]

Understood !! Both Interviewer And Me Are Super - Duper Impressed !!

[@soumiyamuthuraj3516]

Amazing quality, Cant thank you enough. top notch explanation, and nobody teaches DSA in this depth from my learning experience. i dont have words to thank you, may god give you all good health , happiness and wealth to continue this noble cause,

[@Srinivasssssss]

Outstanding Explaination... I cant able to understand by watching this video even 2 times. It doesnt mean, striver didn't explained well. He explained very well. so, people who are not able to understand it well, try to watch it again and again...! Dont search for other videos for this question, and if you even search, I will assure you that, you cant able to find better explaination than this..! Striver, Thank you so much...!

[@vigneshpandi3013]

This man is a god straight from heaven for programmers. The Clarity he has in his explanation is absolutely Amazing! Never seen a guy who is so passionate teaching DSA. Love you Raj Bhai! ❤

[@vinaynagle720]

This is the lecture when I understand hashing properly. Thanks striver👍

[@cinime]

Understood! Amazing explanation as always, thank you very very much for your effort!!

[@AbhishekPandey-dj2eo]

Thank you striver for this ultimate course, I was trying from many days and searching to starts DSA, and this course made me do it Today day 15 😅

[@akworld2739]

hello bhai apki growth kaisi hai abhi kya question ban rhe mai beigner hu mujse to easy bhi nhi ho rhe hai kitna time spend karna chiye ek question mai

[@renewbhagwat5475]

@@akworld2739 same goes for me . ab ban rahe hai kya bhai questions ?

[@joeljacob4685]

Absolutely Brilliant Explanation !! You explained the problem with so much clarity.

[@arunavabanerjee5608]

The best video till now I have seen for this problem . 41 minutes explanation for a single problem is just a next level thing.

[@user-ge4il7kv1n]

One of the best explanation for this type problem. Need to see the video 3 times but at the end got it.

[@user-fc3rj6wl9l]

This lecture is too good 😍🤩 and the Mentor , he obviously needs no introduction 💥

[@simran5048]

That much clarity and explanation 🔥🔥🔥

[@md.ualiurrahmanrahat2400]

This is life saving. Salute!

[@Atharva_kathiyawadi]

kya aadmi h yaar!! dedication amazing 😍

[@Akash-yr2if]

Watching the video 2nd times, first time was yesterday and now things are getting little inside my head. Thnx Striver.

[@ishangujarathi10]

Amazing intuition as always!!!!

[@code247]

wonderful you've taught both approaches together.

[@juliechoudhary9582]

Thank you so much for such an easily understandable course.

[@visheshdwivedi2256]

Making my DSA journey superb ❤ hats off to u

[@transformers-ai]

this series is really commendable. Learning a lot.

[@user-hn3pf5pb3n]

genuinely one of the best cousrse man!!

[@itzmartin20]

what a crystal clear explaination, understood!

[@AyuKG]

thank you so much striver for everything ,today i did this question on my own without watching video but only with my intution it took me around 3hrs but it felt so good and its all because of you. thanks a lot (raj sir)😇❤ @take U forward !!🔥🔥🔥🔥🔥🔥🔥

[@abhaysingh4-yearb.tech.mec565]

Bhai kha placement hui

[@hritikshah54]

Amazing!!💗💗 Also, we can further trim down the code provided in 26:46. If we intialize our HashMap with map.put(0,-1), we can skip checking the condition of if(sum==k)

[@dhruvrawatt9]

following and loving this course ❣❣

[@rohansachdeva627]

Took me 3-4 passes to finally get the thought process through my head. But UNDERSTOOD it finally :)

[@wanderer_ankur]

awesome explanation, i will watch it again and then solve to understand it completely.

[@PrithaMajumder]

Raj, Thanks a lot for This Amazing Video about C++ Arrays Video - 4 Completed ✅

[@footballcreativeeverywhere260]

You are my inspiration bhaiya .. And I am really a big fan of you, blessing me to become like you.

[@naveensaicremsiyadlapalli3769]

excellent explanations as expected.

[@tanmaykarn]

Understood in one go. but had to pause a lot and dry run everything in pen paper. nice question!

[@kushagramishra5638]

understood ! Next level explanation sir 🙇‍♂

[@akashddeepchitransh4537]

Really power packed video 🥲

[@prathameshborse258]

Understood Bhaiya ❤❤ crystal clear and to be point explanation..!

[@krishnasharma-le1mc]

This is the Bestttttt Videooo I had found on KZbin

[@domorebemore3192]

That satisfying song at the end .I always wait till the end for that.😂😊❤

[@charan123rams3]

Thank you so much sir 🙏your keep free time to teaching for us

[@sayakghosh5104]

Understood super explanation as always.

[@luckydev9006]

Finally understood the concept 😮‍💨

[@AdityaKumar-be7hx]

WE can simplify moving to right is we just initilize the sum to zero: int longestSubarrayWithSumK(vector nums, long long targetSum) { int n = nums.size(); // Size of the array. int left = 0, right = 0; // Two pointers. long long currentSum = 0; // Initialize currentSum to 0. int maxLength = 0; while (right < n) { currentSum += nums[right]; // Add the current element to the currentSum. // If the current sum is greater than the target sum, reduce the subarray from the left // until the current sum becomes less than the target sum. while (left targetSum) { currentSum -= nums[left]; left++; } // If the current sum is equal to the target sum, update the maxLength. if (currentSum == targetSum) { maxLength = max(maxLength, right - left + 1); } // Move the right pointer forward. right++; } return maxLength; }

[@himadrimahata8668]

thanks a lot

[@IncredibleJourneyIndianRailway]

thank you

[@tunepa4418]

Exactly, prefix sum is not necessary here. I am assuming he is just trying to explain the concept but it's really not necessary as all the numbers are positives

[@prasannagodiyal6736]

bahut time lag gaya samajhne mai but finally samajh aa hi gaya

[@knl-tu1no]

Awesome sir.Kindly solve String problems as soon as faster. It will be helpful for my placements.

[@priyadarsinipaikaray6271]

dil kush kardittaa sir ji ❣

[@ANMOLAHIRWAR-kg8lv]

a wonderful question and a wonderful explaination.

[@Ramsiya658]

Understood much love to you striver

[@Dreamer_07]

Thanks for the video!

[@user-le3pr5mr1j]

One the most Amazing Problem Solving Teaching Technique stepwise thoughtfully!! 🤩Seen ever anywhere!! Great Thanks! Striver😊

[@vishal_s583]

Great work ❤️

[@dhruvsolanki4473]

Super cool explanation.

[@abhishekgarg5017]

best In-depth explanation

[@ChandanMahara-we4dj]

Thank you so much it helped a lot 🙏

[@konankikeerthi]

Understood. Thanks for your efforts bro.

[@user-ip8ui4tm9x]

Understood great video for arrays problem solving

[@purvi9958]

Thankyou sir for such an elaborate explanation!

[@musicalcasio5146]

in which year you are...?

[@chinmaykonchada]

thank you sir!! for u r wonder lecture and i understood every conceotsir

[@aashishas7044]

nice Lecture. understood clearly bro...

[@LearnwithEase20]

Great explanation

[@subratkumarsahoo3785]

18:17 I can't understood the brute solution using hashing. It goes beyond my head😂..

[@suyashagrawal1102]

bruh try rewatchung the video

[@manavmalhotra5024]

true i figure out the optimial solution before brute and better approach

[@CodeWithMeee]

same, and also hashing means use of hashMap right but where he used Hashmap ? please someone correct me if I am wrong

[@nirbhaybhardwaj4330]

@@CodeWithMeee bro! map is also used for hashing .

[@CodeWithMeee]

@@nirbhaybhardwaj4330 yes, now i understand...I have no knowledge about that earlier. thanks

[@yamini436]

Love u striver bhaiya. You are DOPE!

[@Sillysmiles76]

You made DSA very interesting😄

[@mahendar7733]

understood Great concepts

[@Lucifer-xt7un]

This is called consistency❤❤

[@anmol3749]

Understood Thank you Striver

[@raghumanda2tanush496]

brilliant 2 pointer explanation

[@torishi82]

Samaj aa gaya. Thank you.

[@abhijeetmishra3804]

superb sir understood

[@guneeshvats46]

Amazing explanation striver

[@saouli1632]

37:42 Understood ❤ dada .Thank You

[@_hulk748]

Understood sir thankyou sir🙏🙇‍♂️❤

[@prodevmahi4901]

Extremety helpful video

[@xbenchers1116]

Best Explanation Ever

[@NazeerBashaShaik]

Understood, thank you.

[@DevashishJose]

understood. thank you.

[@shatulbansal4756]

Heyy Striver, Can we use the variable-sized sliding window approach for this question ??

[@AS-gf3ci]

It's a bit complex to learn this in the first go. Maybe it would require re-watching the same multiple times.

[@rohanmajhi1329]

Yeah, I thought that was not my cup of tea but after watching it 2nd time, I got the approach!!

[@AniketKumar-hf2bo]

understood properly thnx for the video

[@fallenAngel-cw9ki]

understood, ty!!

[@ashishphilipthomas]

Thank you Striver May god bless you

[@dinimeegada9167]

Big fan of your teaching and effort anna ❤

[@blue.262]

Anna Are you telugu??

[@prajaktakapoor7520]

"UNDERSTOOD" Thanks bhaiya

[@AkashYadav-md1xf]

understood bhaiya i love this videos and sheet loving the content quality and explanations 🤩😍😇💯

[@riteshbisht94]

Virat Kohli of Programming 🌟🗿

[@vishalakulkarni2620]

Hey did u get how k=3 in 1st eg then in last eg k=6

[@aryansinha1818]

Thank you so much.

[@KarthikDances]

Thank you 🎉

[@vamshi2639]

That OVERALL was crazy !😂😂