6.1 N Queens Problem using Backtracking

[@tanmaychaudhary2801]

It has been 5 years but still these videos are better than new ones by other youtubers.....i am referring to these in 2023...thank you sir

[@jaspreetsinghkalsi2572]

me too mate

[@nishaldevadiga6766]

yeah and his videos will be the best considering future as well! 👑

[@arman9957]

And now it is 2024, still it is better .

[@vyombhatt44]

yea lol @@arman9957

[@yaswanthkavuri71]

Now it's been 6 years lol😂

[@Kuriocity]

*I am from ECE Background, trying my hard for product based companies and I want to thank Sir Abdul Bari for all the Concepts which helps me in competitive programming*

[@manoja538]

Bro u got placed?

[@TG-ql2fv]

No

[@Kuriocity]

@@manoja538 Yes bro,I graduated last year and had 3 job offers

[@NS-sd3mn]

@@Kuriocity lucky u, next year i have placement and i m scared to shit

[@Kuriocity]

@@NS-sd3mn don't worry... just keep practicing and solving questions and you ll get what you deserve

[@saimahumma4724]

Abdul Bari Sir I just wanted to thank you. I have successfully completed my M.Tech with good CGPA and yeah topped at college level. You contribute a lot to my grand success. Thanks a lot. But I regret for I could not find your videos during my B.Tech. Anyways, ALHAMDULILLAH. Now watching your videos to prepare for teaching demos.

[@jayantkeer3416]

You are the best teacher of algorithm in KZbin

[@ayounghosh9218]

thank you for all your lectures, you are like a god sent to us.

[@mohammedrafathali7702]

Ok i can Proudly say that He was my lecturer At College ❤️

[@Shubham_30_12]

which college???

[@siddharthmagadum16]

which college ?

[@cursedblessing9619]

@@Shubham_30_12 Muffakham Jah College of Engineering & Technology

[@kausikkar2587]

@@cursedblessing9619 It is in Hyderabad, right?

[@omerullah]

@@kausikkar2587 yep, he is from Hyderabad. He once came to my college as well for a seminar.

[@sandeepmandrawadkar9133]

That's great contribution Professor! Everything in the presentation is superb - contents - speed of delivery - board usage - selected examples Everything Hats off to you Sir 🙏

[@ojcgv21]

A simple way to explain the N queens problem & solution, love it! Greetings from France

[@aradhyasingh524]

😂🎉

[@nishes]

i'm currently watching to save my self from failing my class thank you

[@AnitShrestha]

Thank you. One of the best description on Backtracking, and its difference with Dynamic Programming.

[@TridibSamanta]

Great ! You are a great Teacher. Thanks for saving my Design and analysis of Algorithm Paper. #Respect

[@aries3690]

Thank you so much for your videos! I am trying to self-learn competitive programming and your videos are a great help to so many students around the world! Keep doing what you do best!

[@LucasMagnum]

You are so good at explaining this. Thank you so much for your time!

[@mranjaan5193]

where are you from Lucas

[@helalali6555]

Abdul bari is a awesome person..he cleared many of my concept....keep helping us Sir

[@kaushalagrawal1620]

halal means food that is allowed to eat allowed ali hahaha

[@helalali6555]

@@kaushalagrawal1620 yes bro you are right but its helal that means moon

[@ASHJACX]

it was a great explanation, you deserve million views

[@harixhyadav]

whatsup bro

[@jivanmainali1742]

@@harixhyadav got placed??

[@samiazaman5240]

This is such a wonderfully satisfying concept, and a great video, too. Always love sir's peaceful energy.

[@grasstoucher856]

exceptional articulation sir. I myself get's confused going through it step by step while you're able to trace it accurately for each node. Really inspiring.

[@kimmara6475]

Please shared me if you got any notes for tis.

[@zahid_9217]

I have done crazy amount of practice finally I understand it perfectly. keep doing practice you are going to master it.

[@Kuil..]

Those who watch in 2024 assemble here guys 🫂😍

[@subinaypanda9936]

This is very good sir. I was in very confusion of brute force searching of solutions of Sudoku. But the lectures of you have cleared this. Your explanation is too good and I am really very happy after seeing your videos. Thank you sir for teaching us.

[@Lucifer-jl9vh]

Thank you Abdul Bari sir for your videos on Algorithms. They are helping a lot of students like me. Your work is very much appreciated.

[@shubhampandey8765]

Can't be grateful enough for this Man's work , hats off.

[@parneetkaur2588]

Everytime i used to watch your lectures but never bothered to comment...but sir you way of teaching is superb! Thank you for your lectures.

[@shoaibMalik49]

Amazing sir. I loved your videos.. I'm watching these videos a night before exams

[@aniruddhsingh3501]

sir love your videos...kindly consider including the algorithms along with the explanation

[@saksham8566]

Very nicely explained! And not too hard English used 😋

[@rajivtechknow393]

After learning from your video lecture I completed certified course very easily u are great🙏

[@fahmidhossainSakib]

this guy is amazing ! teaching us with lots of care and effort.

[@vman049]

Note that the reason you're able to restrict the first queen to the first row, second queen to the second row, and so on is because they are all queens, so it doesn't matter which queen is on which row -- they will all function the same way. In other words, the ordering of the queens doesn't matter. You could just as well put queen 3 in row 4 and queen 4 in row 3 and achieve the same result. We are forcing there to be a single queen per row, since otherwise two queens would be under attack, and are just interested in specifying which _column_ the queen in each row will be on.

[@soumyajitdatta9016]

Bro u just said something that will change the way earth revolves around the sun

[@sidindian1982]

Well Explained the Solutions .. specially that mirror image of last vedio footage 13:30 ... Thanks Sir

[@sergekamga915]

Your explanations are super clear. Can you add videos about topological sort, strongly connected components, and bipartite graphs?

[@DHARMAKD-y5b]

the way u are teaching is excellent sir.please continue to make videoes

[@vigneshrao4965]

Hi sir I saw the video of n queens problem ,it helped me lot to create my own presentation Now I am in need tug of war problem using backtracking

[@patrickmayer9218]

*3 things to worry about so queens don't attack each other: same row, same column, and same diagonal *generate a state-space tree *the default is that the nth queen is in the nth column and nth row (they form a diagonal on the board from left to right) the state-tree backtracking starts at 8:40 Thanks for the video!

[@magentata1942]

without your lectures we are wasted sir♥️♥️💯🔥

[@SPOIDERMON_1]

Tb tera career gya

Brilliant explanation. Thanks, Professor Abdul!

[@mukitmahmudul2616]

I love ur way of teaching sir.u makes the lesson easy.Love from bangladesh.

[@pinnumishra4563]

What a great way of explanation. Thank you so much Sir G

[@supriyasaha6168]

Thank you so much Sir for explaining it so clearly🙏

[@syedmahasibali2324]

Made the problem easier well done Great privilege to see this

[@supriyachauhan5341]

Don't know what I'd do without you!!

[@Recordingization]

Thank you,Sir.You made the searching problem easy to understand.

[@dan-gu1ty]

Abdul sir, you are the best ♥

[@dr.vinodkumarchauhan3454]

Sir, I suggest you to make comments about the complexity and algorithm/program for each problem, in that way it will present complete discussion about a problem otherwise students need to search other content for getting answers to these questions. Thanks!

[@user-wc1sm8cj8s]

Very great explanation. Thanks sir, you earned my respect

[@jonelleyu1895]

Thank you Sir Abdul Bari! One question - at the end, you mirror the solution 1 vertically and get solution 2. Why not keep mirroring solution 1and 2 horizontally to get totally 4 solutions? Thank you.

[@Inndjkaawed2922]

if you mirror them horizontally, you get the same solution as the mirror image or rotating the positions clockwise or anticlockwise

[@rajingajadhar4135]

First year here, this was extremely helpful!

[@nandanbanerji8309]

Really Great Prof. Bari. very nice demonstration.

[@carolineignacior.4480]

you are just THE BEST

[@akashmaurya5338]

how many of you are watchin 1.5x or 2x hit like here kabi kabhi nhi hamesha lagta hai ki sir ich bhagwan hai.... akash gaytunde

[@micimaos]

nopp,.. Normal (Y)

[@CliffCarmichael]

Damn, you must be either very alone, or very deprived in life.

[@ritam_chakraborty]

Watching in 2.5x

[@abhishekguptasarma2060]

@@ritam_chakraborty That will be overkill and somewhat unbelievable..

[@ritam_chakraborty]

@@abhishekguptasarma2060 no man, 2.5 is totally resealable.

[@ajithnayak2754]

@Abdul Bari Sir, your explanations are so amazing!!

[@phdgateway4127]

Dear Guru...! Its very great that you've explained well .but we as a learners we'd also expect it in Algorithm tracing .if you possible could you please make it out sir

[@rajeshg3570]

I'm little confused with this. at 3:44 , you are saying, we will not consider the attacks and try to arrange. Then you are saying, let's not place Q2 in same row or same column. This is where I'm confused. Why not place Q2 in either same row or same col when we say ignore the constraints for sometime. Any specific reason or am i missing anything.

[@ankoor]

n-Queens Python: class Board(object): def __init__(self, n): self.n = n self.board = [[0 for _ in range(n)] for _ in range(n)] def solve(self, row, result, output): if row == self.n: output.append(result[:]) return for col in range(self.n): if self.isSafeCell(row, col): self.board[row][col] = 1 result.append((row, col)) self.solve(row+1, result, output) self.board[row][col] = 0 result.pop() def nQueens(self): result = [] output = [] self.solve(0, result, output) return output def isSafeCell(self, row, col): # Vertical check for r in range(row-1, -1, -1): if self.board[r][col]: return False # Main diagonal check r = row - 1 c = col - 1 while r >= 0 and c >= 0: if self.board[r][c]: return False r -= 1 c -= 1 # Minor diagonal check r = row - 1 c = col + 1 while r >= 0 and c < self.n: if self.board[r][c]: return False r -= 1 c += 1 return True def display(self): for row in self.board: print(row) b = Board(4) b.nQueens()

[@dibyajyoti3038]

Java!??

[@minato7621]

@@dibyajyoti3038 python

[@kadirilavanyareddy6033]

Thanks sir... U gave us THE BEST lecture

[@arkapravabhattacharya9472]

After the first arrangement of all the queens,shuffling of q3 was done and so was done for q4. As q4 was already in 4th column why you have written q3 in 4th column?

[@Shivam22.1.97]

wonderful teacher u r ..........sir most of the student try to study cormen book of algo but failed to do so ......sir plz make videos of cormen book explanation .........it will be of grt help to many..........thanks

[@sarahchopra6171]

Amazing explanation

[@KovalovAnton]

Like -> Watch -> Practice -> Repeat

[@saicharan8675]

Really helping your videos alot professor.. Thank you

[@srikanthuppala8297]

Great Sir. Clear explanation. Thank you so much Sir.

[@christopherd7029]

Sir, can you please solve 8-queen problem? I really like your explanations 👍😊

[@christopherd7029]

Abdul Bari okay thank you sir

[@harshgupta2710]

it would be more better if u include psuedo code with these!!

[@harshgupta2710]

although the explation was ultimate and well explained :)

[@KaranBulani]

Abdul Bari you haven't yet

[@chiragpariani7828]

@@abdul_bari Please add

[@yashpadia940]

Expecting an algo for the same

[@fameflu]

@@abdul_bari where psuedo code?

[@udaynithin8161]

sir we are back benchers so sorry for this meru explain chesey way ke okkati chpali sir me modda ke salam me gudha ke gulham hattsoff sir for passing out in this subject

[@glitchmaker0309]

This guy teaches a million times better than my gibbering algorithm teacher.

[@chinmayiadiga515]

one of the best AI videos that I have come across in youtube.. well explained .. Good job sir..

[@u-mimi]

wow.. It's really fun. I'm not good at English but this lecture is easy to understand. I already know backgrounds, but it's very fun to me. now i'm conside buy ur other lecture.

[@chamnil8666]

Thank you sir .you are a great teacher.Great explanation.I am subscribed.

[@ben-hah-meen]

For the equation at 8:15, should the 3 above the sigma be n-1 when you change 4 to n? i.e. 1 + sigma i=0 to n-1 [pi j=0 to i (n-j)]

[@vinodjindal7210]

it a simple permutation sigma(npi) where i varies from 0 to 4.

[@sharda16april]

yes, that is correct. I corrected my notes.

[@k-ananya9657]

Thank you sir! Really you are a great person, lots of love and respect

[@abanur3163]

thank you sir i want to ask do you have any tution class inside india that you train as

[@ajinkyaadhotre5336]

idk about his pvt tutions but he is available on UDEMY ,search for him on udemy

[@abanur3163]

@@ajinkyaadhotre5336 yes thanks, later i realize that he is available on udemy and i pass this subject

[@arunkumaragrawal7486]

How can I solve 8 queen's problem the tree become very complicated... Plz sir advice me what to do...

[@niharinthselva3613]

@@abdul_bari yes that's a kinder way to put it xD

[@naziyafirdoussayyed8491]

I would love to skip the question of 8 queen problem 😁 if it comes in exam😋

[@Endrit719]

@@naziyafirdoussayyed8491 lol , I've got the exam on friday if the question is 8 queens I am gonna say that Abdul Bari said don't try with 8 queens xD

[@naziyafirdoussayyed8491]

@@Endrit719 hahahahhaha... Good one. But thank God I passed in exam without solving the 8 Queen's problem. Hehehe

[@naziyafirdoussayyed8491]

@UCTeCKWvk68v3WZsJ0ntufFQ areeee..hahahha " I love u " kis liye

[@michaelujkim]

What do you do about the solutions that don’t have q1 in the first row? Wouldn’t that open the solution space?

All fun and games until you gotta write the code for that baby

[@chandud4255]

Explanation is awesome but please add programmatic pseudo code also

[@phoneix24886]

There is a great video on Neetcode which uses a brilliant trick to solve this problem.

[@abhinavdadhich2311]

god aur banao aaise log duniya mai itne clear minded

[@soumodipsengupta9902]

Perfect explanation, Now I am able to code and understand deeply this solution !

[@prayagshah1247]

Thank you very much sir I have clear this subject in just two days before exams👦

[@Mr.Yadav1997]

You are excellent teaching in DDA subject TQ sir

[@shasvatnayak2329]

You are an Inspiration sir✨

[@Ashik-iu1oh]

Thanku sir you are doing a great work ❤️😍💕

[@sshiv908]

my favorite teacher on utube

[@singhiitian3150]

thanks one ques that i think u have the row in which the queen 1,2 etc can be in otherwise there will be many more soln jus by onterchanging gthe pos of the queens .

[@Momo-qr3rd]

You are the best teacher sir

[@jishnuprasadhemaraghunanda4384]

Amazing sir Understood in a single go

[@syedsaifahmed4103]

Assalamualaikum sir. Your videos helped me a lot in studying and writing the exam very well and more than expected. I was feeling low before watching your videos bur my exam went brilliant. Thank you soo much sir. Me and all my frnds thank you a lot. May Allah bless you with success and happiness in your life. AAMEEN 😇😇🙌🙏🙏💝💘💞

[@syedsaifahmed4103]

@@abdul_bari thank you once again 😇

[@Flutterdev6391]

U serve the whole world

[@sufyaansaeed7158]

thank you so much for all your videos, major help!!

[@tobiahrex]

Can you/someone explain why we wrote (4-j), I was expecting Big-Pi (sum of products) right of Sigma. I understood everything but , can we write instead?

[@yeet3810]

Thank you master you're the best explaning👍

[@nishawandile3097]

Thank you very much sir for so easy explaination.

[@Gayathri_G]

Best explanation ever!!!

[@viky293]

Many Good things are free and under appreciated.

[@gurunathreddy6908]

Hi, I have one doubt using brute force approach is it possible to fit the elements in 3X3 matrix.

[@shreyoshiraychaudhary8808]

Sir, can you please show the steps to find the time complexity using the recurrence relation T(n) = nT(n-1) + n^2

[@manvendrasinghsuriyal2144]

Correct way of explanation

[@Desireanshu]

Thank you sir for clearly explaining step by step

[@likhitha2350]

For 8 queens do we have to find all the solutions or one solution is enough?

[@veenuupanchal5854]

You are a great teacher.