Trapping Rain Water || Best optimization || O(N) Time O(1) space || Intuition with Code and Example

Given an array arr[] of N non-negative integers representing the height of blocks. If width of each block is 1, compute how much water can be trapped between the blocks during the rainy season.
Input:
N = 6
arr[] = {3,0,0,2,0,4}
Output:
10
Explanation:

[@jatinbhatoya8420]

oh god, you explained better than striver. hats off. Once you said the word limiting, i understood the whole algo and coded it myself.

[@piyushsingh9320]

true,better then big youtube channels

[@yeswanthh5068]

Yaa🔥🔥

[@anandyadav_]

true!! limiting word helped : )

[@lostcyrus8578]

i also came after watching striver..you explained better

[@radhikagokani3660]

Exactly !! Was working on the problem for hours ! LIMITING was the word that made everything clear !!

[@RassieVanderDussen-mc8um]

It never happened that I came to understand the solution from your video and not understand it. Your intution and approach are so easy to understand. Thanks and please continue this great work.

[@hema4266]

You used the right words to build intuition and everything seemed so simple!!!! Thanks a lot

[@SirAkPandey]

Hats off to your efforts.. You're the most underrated educator on this platform 🙏🙏

[@krishnasahay9694]

Finally got an approach with constant space. Best explanation!!

[@aishwaryakulkarni9452]

This was the best explanation so far, concepts are clear! Thanks a bunch🥺 Your channel is so underrated :(

[@b2aquantschool798]

Even this video is two year old and I am watching it right now, after watching multiple other video solutions ,I can confidently say that your explanation is the best out of all I have watched till now. This video is ever green. Thanks for your effort. Please Don't quit from making this type of video, keep it up at least for your viewers. The only word I can say about this video is "Excellent".

[@raufurkhan9191]

Such an easy and lucid explanation. One of best explanation..Kudos..🙂

[@anonXoXoXo]

oh my god,such a nice explanation . its not just this question ,when no one is able to make me understand the solution ,its always your solution which help me understand .

[@rudra-18]

Nice explanation with such a clean code!

[@bhargavinaik8145]

Thank you so much for this explanation, I had solved it with 2 arrays, was struggling alot to understand the O(1) space logic. The words you used really helped to unlock that link.

[@naredlaaalana9371]

Thanks for the detail explanation. Now I got to understand the intuition behind using the two pointer approach to this problem

[@ashishtiwari6000]

Must say you are simply awesome !!!!!!

[@rabindrapatra7151]

Beautiful

[@bharathkumar5870]

thanks again,learning important problems from ur channel

[@harish5466]

Best and easy explanation have ever seen. Thank you

[@ashutoshlawaniya9833]

Really, it is awesome 🔥 Keep it up .

[@yeswanthh5068]

Wonderfull explanation,thank u very much 🙂🙂

[@Yash-fh7gm]

thanks for this great video and amazing explanation

[@addankihasith4672]

Thanks for the explanation and the efforts you put in making things simpler in this video

[@KunalSharma-cj5hc]

Very nice explanation literally. You just gained one subscriber.

[@brijrajsinhgohil6576]

your intuition is the best!

[@avijitmaity7436]

the explanation is to clean to understand the problem and also simple. thanks

[@rohithjakkani8343]

Very nice and fast Explaination.Good Concentration till last minute.

[@jagan2350]

your explanation for the problem are greater ,thank you for the video, it was very useful to me

[@rinkygarg7350]

though I saw this approach many times but couldn't understand before so keep looking for more. Only, in this video, I could actually feel that I understood the concept. Thanks and keep it up. 👌👌👏👏

[@sudeepgupta57]

Thanks for the great explanation

[@bishaladhikari9499]

Brilliant!

[@gauravverma2901]

Thank you so much ma'am for such a great Explanation😍

[@lakshyakumawat9710]

Great explanation 🔥

[@bikramshahi8512]

great explanation , you deserve more likes and suscribers....

[@danussh]

Perfect😍

[@techiestart3233]

U are doing great job 🤩thankyou so much for sharing your knowledge.please also make a video on your interview questions

[@arshdeep011]

Best video for this problem!

[@adityaband6919]

amazing explanation

[@kumaravinashsinghabnish4021]

Really underestimated teacher you are 🎉😮 Awesome 💯 I had watched almost 7 videos of you since morning 🌅 Exclaimed Explained

[@gitanjalikumari9262]

Thankyou.. great explanation really😊

[@sheraurshayri2033]

nice explanation than striver greatttttt

[@Mahmmadhusen072]

best video thanks. i understood

[@ManishKumar-jz2jr]

Great explanation. Subscribed

[@abhishekkarn8918]

Uncle is extremely cute btw :). Great video though Alisha :)

[@charand9597]

very intutive explanation brilliant👑👑👑👑👑👑

[@priyankpatel1580]

Greatest explanation ❤🎉 tnx

[@drizzle01]

20:04 Uncle ji parnam XD, great explanation btw!

[@ankit80354]

thankuu so much dear🥰.

[@rakshitbro7601]

you strudied from striver and explained bettter than him very well alisha

[@narendra7556]

great Alisha thank you

[@kushalshukla444]

nice explanation

[@Alan-bu2hi]

Thank you!!!!!

[@ProgBoost]

Thank a lot ☺

[@nagendrapp2213]

nice explanation and if you don't mind could you please reduce the screen size (zoom out ) for all your videos so I can able to see whole code (screen) and also please make a video on how to maintain the consistency (problem solving ) 😊

[@ayushsinghrathore360]

Thanks 👍🙏

[@maddycoder1294]

its very helpful thanku

[@SleepeJobs]

Thank you ma'am.

[@raedhasan2240]

thank you

[@shivanshgupta1509]

ThankYou mam!!!

[@venkataramanan6354]

Nice explaination, Can you please create a video for time management, like the sleep crisis during preparation, It feels like a sleep deprivation is on the way, please help tackling.🙂

[@shubhamsukum]

Thanks!!

[@sharadkumar6658]

Nice mam. It was quite good solution.😇😇

[@sharadkumar6658]

Mam plz upload leetcode daily solution too.🙏🙏 It really help a lot..

[@nasirkhansirajbhai8016]

amazing skills.. thank you, could you please post some content on linkedin as well?

[@expert_solver]

when you said limiting bar decide ans that point, game is over👍

[@user-sm7zo5zd9t]

Thanks mam

[@satyajeetkumarjha1482]

Actually, ur code could have been more intuitive if u calculated left max and right max and then did leftmax

[@AnoopSingh-hx4wm]

tq mam 🤗

[@saveethanotessharingsharee1155]

Can u explain on placement problems of java

[@devadityasati7757]

i love your way n u

[@SelfImprovementtip]

class Solution { public int trap(int[] height) { if (height == null || height.length == 0) { return 0; } int left = 0; // Initialize left pointer int right = height.length - 1; // Initialize right pointer int leftMax = height[left]; // Maximum height to the left int rightMax = height[right]; // Maximum height to the right int ans = 0; // Variable to store the total water trapped while (left < right) { if (leftMax < rightMax) { // If leftMax is less than rightMax, process the left side left++; leftMax = Math.max(leftMax, height[left]); ans += Math.max(0, leftMax - height[left]); } else { // If rightMax is less than or equal to leftMax, process the right side right--; rightMax = Math.max(rightMax, height[right]); ans += Math.max(0, rightMax - height[right]); } } return ans; } }

[@youtubechannel-ub1xr]

491 likes are too less for your explnation!

[@prajjwaldubey5787]

the space complexity is O(n) not O(1) as you mentioned it in thumbnail please change it

[@studywithsmartwork9953]

we are not using any array or stack so how the sc is o(n)

[@vinamrasangal8436]

alisha ,u r a gud girl