BS-9. Find Peak Element

Problem Link: bit.ly/3BEDvZC
Notes/C++/Java/Python codes: takeuforward.org/data-structu...
We have solved the problem, and we have gone from brute force and ended with the most optimal solution. Every approach's code has been written in the video itself. Also, we have covered the algorithm with intuition.
Full Course: bit.ly/tufA2ZYt
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0:00 Introduction of Course

[@takeUforward]

Sorry for the delay :( But I had a product launch, for which I had to spend most of my time in the office. I am back, will try to come with 1/2 videos daily now

[@charan123rams3]

Thank you so much sir 🙏 Sir first take rest whenever you have free time then post sir 🥲

[@shivanshumishra0560]

Thankyou so much bhaiya for all videos ...🙏🙏❤️❤️ Your content is >>>> whole KZbin

[@sudhanshushekhar4222]

Understood

[@sayakghosh5104]

Was trying this for the past 2 days, couldn't solve it. Took 1 day break came back at it again with a fresh mind, could solve it in one go by myself. Thanks, your series instills such confidence in me always.

[@OrderEmperor]

no one asked

[@sayakghosh5104]

@@OrderEmperor 😂 ok bro.

[@paraskashyap7362]

@@OrderEmperor no one asked nested(no one asked if no one asked or not)

[@paraskashyap7362]

@@arunm619 fair enough

[@Kj89865]

@@paraskashyap7362 calling in return statement (recursion)no one asked if no one asked or not that no one asked :----) *without breaking condition

[@shivanshugarg807]

Thanks striver I completed all your sheets , like twice , they boost my confidence , before watching your solution , i try every question for 30 mins , and regardless i am able to solve it or not , i watch your video for better understanding and side by side mark improtance of question and make notes for revision

[@anujrathore5726]

NO ONE CAN TEACH LIKE STRIVER, HE GIVES HIS 100% to his lectures. he want to teach , he compleltly go into the state of teaching , like with full FOCUS & DEDICATION . he enjoy to teach . and all of this FREE OF COST , LEGEND AKA RAJ VIKRAMDITYA BHAIYA (STRIVER BHAI OP ) ❤

[@ishanshah3309]

the best about this video was the thinking process of how to arrive from linear to binary search in problems like this. execellent stuff.

[@ritvikryadav9667]

Hey Striver, Your videos are pure gem. Certainly the best DSA course on the planet. Keep going. God Bless You!

[@yashgarg3899]

i have solved these questions already so before but still i watch every video of you because i know there will be something different which ultimately enhance my code writing or intuition skills.

[@iWontFakeIt]

was waiting for these past two weeks and you showed up with another awesome explanation! Thanks dada ❤

[@mriit3025]

the extra afforts for the edgecases is appreciated! keep working on content like this...

[@viveksinghrajput2725]

Best explanation on the KZbin thank you soo much....each and every second of this video is informative.

[@oguluribrahmaiah1301]

Commenting Understood is just a simple thing for your wonderful explanation !!! Thank you So much for your lectures Striver

[@mahendrachourasiya7444]

SUPERBBBB Explanation! Thankyou so much for your great efforts.

[@Dreamer4lyf]

Amazing explanation Striver my man! Hats off to you for all your hard work for the community.

[@ishangujarathi10]

GOD LEVEL INTUITION AND EXPLANATION STRIVERRR TYSM < 3!!!

[@pizzagamingyt9712]

Bro u are the most helpful person for all engineering cse student 🧡❤

[@GalaxyStart62]

it's a blessing that you are in youtube, but on the other side , people are enjoying DSA now, hence , competition is drastically increasing too.

[@AdityaGarg-hl7ri]

Thankyou striver, still maintaining that low=m+1 and high =m-1 thing which makes it super easy to understand!!

[@madhulikaghosh3876]

Your explanation is crazy. You are really doing a very good job.

[@Dipanshutripathi2407]

Filled with full confidence after watching ur videos.

[@rohitkumarpilania94]

welcome back, waited for you every single day

[@Raj10185]

Tysm first time i got clear cut intution of finding the peak element :) tysm again UNDERSTOOD EVERYTHING:)

[@socify4410]

solved by my own thanks a lot Striver Bro keep spreading the knowledge

[@cinime]

Understood! Super awesome explanation as always, thank you very much for your effort, and congrats for your product launch!! Is this idea used to find the derivative local maximum / minimum?

[@Manishgupta200]

THe last one infinite loop example was very helpful to understand the problems condition clearly.

[@ankitdhattarwal2286]

There are one mistake in the code when try solve problem on GFG then not pass all the cases the mistake is if(arr[n-1] >= arr[n-2]) return n-1; // use the equal sign also so that can pass all the cases and thank you so much to provide best content

[@lavanyam3224]

yes, that is because the definition of peak is different in gfg. It says the peak can be greater than or equal to its adjacent elements (a=b) but in leetcode, the peak should be strictly greater (ab)

[@rakshan3323]

@@lavanyam3224 And that peak definition seems to be correct because here, it doesn't cover the case when all the elements are equal.

[@hashcodez757]

Understood very well sir!! No words for your appeciation bhaiya

[@DeepikaKondamadugu]

Didn't even look for completion time of the video!!!.....So that much interesting your videos are❤

[@abhijittalukdar6995]

Bhaiya I solved this without seeing the video. Because i have learnt the concepts from your earlier videos. Thanks and LOTS of LOVE.

[@user-ti3bd8mp1w]

understood Thank you striver for such an amazing explanation...

[@graviton001]

Was able to do it myself 😮 thnx for building up my logical thinking ❤

[@kenkaneki669]

Damn, was eagerly waiting for this!!!

[@hareshnayak7302]

Understood,thanks striver for this amazing video.

[@dank7044]

absolute beauty of a question

[@deepanshudahiya8966]

An amazing question learning new patterns of conditions in binary search

[@rohitsai806]

Fantastic teaching...!

[@Mousam_Sharma]

Understood .best Explanation 👍

[@manavsingh5919]

Thank You Striver..Understood everything🙂

[@kayathrivenkatesan7712]

Great video sir..thank u for saving us

[@girivardhanvelpula]

00:04 Find the peak element in an array 02:16 Identifying peak elements using the concept of infinity assumptions. 06:42 Peak element finding in a sorted array using binary search 09:03 Binary search to find peak element 13:59 Identifying peak in decreasing curve 16:22 Dealing with the cases of the first and last elements as peak elements. 20:38 Finding peak element in an array using binary search 22:54 In a decreasing curve, the mid element is greater than the right element. 27:08 Binary search can efficiently find the peak element 29:08 Algorithm to find peak element in an array

[@Ald0Abdiel]

Amazing explanation! thanks teacher :)

[@Josuke217]

This was pretty easy, finally solved it on my own.

[@noone1000_xyz]

at the end of video i am just surprised.......understood very clearly.....thankssss a lottttt striver......

[@piyushwandile4152]

great content no one teach like this atleast for free

[@AnmolGupta-oj4lm]

Understood Very Well!

[@dayashankarlakhotia4943]

Very well explained. Understood

[@rashikhandelwal4121]

Bestest explanation ❤

[@snehashisratna9074]

luv the way u teach

[@sukritinarang5016]

Great Playlist . 👍

[@Aman_Panchal27]

understood, you are BEST !

[@mehrabhossain8225]

you are really great one ..

[@akashddeepchitransh4537]

Mind blowing video..

[@user-gl4fs5hn3m]

The man who is making every CSE student's career bright

[@ariesgaming4580]

Understood perfectly!!!!

[@gokulkrishnanj]

Nice explanation on that hidden test case

[@user-to6mg5mz7n]

Excellent explanation

[@samuelfrank1369]

Understood . Thanks a lot.

[@kingbadshah452]

thanks striver understood everything

[@dipingrover1970]

very good explanation .

[@ashokyadavfqplmgxjia4668]

far better than other vedio

[@NazeerBashaShaik]

Understood, thank you.

[@jagannathan1014]

Dude you're a god🙏

[@theengineer8301]

Hi Striver, this was an epic explanation. Hats off! However I think we can only check the left element of mid. If greater then eliminate right. Else eliminate left. No need for the other if condition. class Solution { public: int findPeakElement(vector& arr) { int n = arr.size(); if(n == 1) return 0; if(arr[0] > arr[1]) return 0; if(arr[n-1] > arr[n-2]) return n-1; int low = 1; int high = n - 2; int mid; while(low arr[mid+1] ) return mid; //mid-1 greater than mid, peak on left,eliminate right if(arr[mid-1] > arr[mid]) high = mid - 1; //peak on right, eliminate left else low = mid + 1; } return mid; } };

[@expanse8846]

he explained it by the end. it may lead to an infinite loop if there are multiple peaks.

[@casafurix]

wow, the reversal peak, beautiful

[@boomerofficial7177]

Kya question samjhaya hai bhai 👍👍👍

[@Shunya_Advait]

Understood Sir.👌

[@harshilpatel3205]

Thank you striver 😇🙌

[@saambpatil9912]

iNSTEAD OF ADDING THE LAST CONDITION WE CAN CHANGE THE ABOE CONDITIONS TO : else if (nums[mid] < nums[mid + 1]) { low = mid + 1; } else if (nums[mid] < nums[mid - 1]) { high = mid - 1; } COMPLETE CODE: class Solution { public: int findPeakElement(vector &nums) { int n = nums.size(); if (n == 1) { return 0; } if (nums[0] > nums[1]) { return 0; } if (nums[n - 1] > nums[n - 2]) { return n - 1; } int low = 1; int high = n - 2; while (high >= low) { int mid = low + (high - low) / 2; if (nums[mid] > nums[mid + 1] && nums[mid] > nums[mid - 1]) { return mid; } else if (nums[mid] < nums[mid + 1]) { low = mid + 1; } else if (nums[mid] < nums[mid - 1]) { high = mid - 1; } } return 0; } };

[@user-pz4uy2qu7r]

Well understood.

[@sallu_-bhai]

Love ur apoorach sir 😁

[@hariomtiwari7605]

UNDERSTOOD 👌👌👌👌👏👏👏👏

[@siddunihary]

Strivers Sir You Are The Best

[@ganeshjaggineni4097]

NICE SUPER EXCELLENT MOTIVATED

[@CodeMode9313]

shukriya habibi ..

[@saravanajothigandhirajan6570]

Loved it

[@parassetia4964]

Understood boss!!

[@harshit.53]

bro u are great...

[@sajjanshah4508]

Understoood👍

[@md.imrankhan6912]

Legendary Boss

[@utsavseth6573]

Lovely striver.

[@harshitsingh3510]

can we simply find the largest and return that index , it will also give the peak😜

[@jitesh_khurana]

UNDERSTOOD SIR

[@senseiAree]

Understood ❤

[@user-or5oz1pk2x]

Thanks a lot Bhaiya

[@abhay9994]

Thank you.

[@pavansai2859]

God level ❤‍🔥

[@abhishekpardeshi8506]

Understood 😊

[@culeforever5408]

understood 😇

[@user-is6ky7pp2n]

Understood !! 😎😎

[@ChethanV-w8l]

Thank you

[@Balaji-vx6uj]

Understood👍

[@jayeshtotlani]

what happens when mid mid+1 and mid-1 element are same and hence peak can be on any side ? is that test case not included on leetcode where there is only one peak and mid mid+1 and mid-1 are same

[@swetaacharya2969]

Thank you bhaiya ❤

[@NewtonVarma]

If we are to return an array of indices where peaks are found(all peak) can we still apply binary search by making some modifications and applying if else checkups. 🤔

[@yagnasriparsi9500]

Hey To use Binary Search Array should be sorted right but we are not sorting the array

[@Shivi32590]

thank you

[@Sanjaysview]

good one

[@Raj10185]

code for the same :- int findPeakElement(vector& arr) { int n = arr.size(); //checking done for initial cases where finding and is very easy if(n==1) //edgecase1 return 0; if(arr[0] > arr[1]) //edgecase 2 return 0; if(arr[n-1] > arr[n-2]) //edgecase 3 return n-1; // now apply bS on remaining part int l = 1; int r = n-2; while(larr[mid+1] && arr[mid]>arr[mid-1]) { return mid ; } else if (arr[mid]>arr[mid-1]) //mid on the increasing path that means our ans will be in right side l = mid+1; else // mid is on the decreasing path peak will be on left side r = mid -1; } return -1; }

[@AppaniMadhavi]

not working for all testcases in coding ninjas

[@dipakgupta2533]

Understood!! :)

[@ymishra7790]

Understood! 😁

[@riteshbisht94]

God level content 🥵 🔥🔥