N Queens - Solution | Recursion | Data Structures and Algorithms in JAVA

[@NiteshKumar-do4en]

No teacher is present currently who can explain this topic in easy manner amazing job

[@Pepcoding]

I am glad you liked it. I also hope that you are watching till end and trying to understand the what, how and especially why of the problem. If you like my efforts, I request a review g.page/Pepcoding/review?rc

[@jerichocasey2078]

InstaBlaster.

[@047gauravkumartiwari5]

@@Pepcoding Ye baat copy pasted message ke form mein hi kyun likhna. Kabhi normally bhi bol diya karo

[@ashutoshkumar4099]

sir no other teacher has the guts to analyze recursive programs completely step by step and draw state space tree for it...Iam really getting to know how to approach solving recursive programs...words fell short thanking you...please keep the good work going

[@Pepcoding]

Glad to know that you liked the content and thank you for appreciating. The love and respect which I get from you people keep me highly motivated and the same I am able to forward It to you people through my videos. So, keep motivating, keep learning and keep loving Pepcoding😊

[@secularguy________]

@@Pepcoding love u sir

[@rohanjaiswal64]

I watched it twice and the more I watch it ,the more I understand about the working of the Euler. Amazing explanation!!

[@Pepcoding]

Thankyou beta! I am glad you liked it. I hope that you are watching till the end and trying to understand what, how, and especially why of the problem. If you like our efforts, will you like to write a few words about us here (www.quora.com/What-are-the-good-websites-to-learn-data-structures-and-algorithms )

[@AHMED_MOCHI]

After watching 15 videos regarding N Queen problem, no one was able to deliver this concept this easily as you did sir. Thank you so much !

[@adityagupta375]

At 10:00 he's speaking the language of the gods 🥺🥺😍😍 amazing explanation sir

[@adityagupta2253]

I was stuck in implementation of isSafe method and your tutorial helped me to understand that. Thanks a lot for the clear explanation.

[@Pepcoding]

Thankyou beta, I am glad you liked it. I also hope that you are watching till end. Will you like to write a few words about us here (www.quora.com/What-are-the-good-websites-to-learn-data-structures-and-algorithms)

[@ashutoshtiwari4719]

Still if u didn't get the problem then no one on this planet can teach you better than this ❤️

[@Pepcoding]

I am glad. Keep learning. Keep supporting. Your kind words are the kind of motivation that truly help me in making more and more content. Especially, these days, not everybody is generous with motivating anybody either. It means a lot

[@rupinderkaur-dj8ib]

next level teaching,although ive paid for the course(gtbit program) still i watch your videos instead of attending zoom classes.

[@Pepcoding]

Beta, class zrur attend kre because standalone videos itni benificial nh hoti, jitna live classes hoti h.

[@deepakojha3216]

hi bro can i contact you to know how is live programs can you provide me your instagram id so that i can contact you

[@MusicalLifeViB]

I had been facing problem in recursion and backtracking but I watched this playlist and now do feel confident to atleast approach the problem. Thanks for this world class explanation and analysis.

[@Pepcoding]

Glad you liked it! Keep learning. And for better experience, visit nados.io, where you will get well curated content and career opportunities.

[@MusicalLifeViB]

@@Pepcoding sure and thanks again!

[@mayur_madhwani03]

3 mahine pehle jab pehli baar attempt ki thi ye problem laga tha kabhi solve nahi kar punga. Aaj jab ye video dekha kaafi jaldi solve ho gayi. Thank you for teaching in the best way. Belated Happy Teacher's Day sir ❤

[@ZSHADOW18]

Why is prints all possible solutions can anyone explain, i mean it should just print the first possible solution but instead the code prints all possible solutions...

[@karakib2k17]

Thank you from Bangladesh. Amazing video. I love your explanation and dry run system.

[@creativegiant148]

No teacher is as dedicated as him to make us understand the topic please guys subscribe the channel he is great

[@Pepcoding]

Thanks buddy! Always keep supporting and loving like this.

[@nknidhi321]

Never thought N-Queen would be this easy.. All credits to you..🙏❤️

[@Pepcoding]

Will you like to write a few words about us here (www.quora.com/What-are-the-good-websites-to-learn-data-structures-and-algorithms )

[@shubhamkhuntia2412]

lelo sir anumati, aap h rkhiye unko. aaajse Anumati aapki

[@debbh274]

Man, the clarity of your explanations is mind boggling.

[@prakhar_kesar]

Probably the best explanation of N-Queens Ever. #Respect.

[@nitin9042]

Student at someother x academy learning from pepcoding thats how much good he is

[@krishnapandit_vlogs]

Lajaawab explanation sir ji.... Excellent job... I am your big fan sir ji....

[@chandanverma5179]

Sir this may sound stupid but why didn't you solved this like expectation faith Meet expectation from faith .. Can we not solve this like that????

[@RBNrocks]

Sir thanks a lot for explaining in so much details. I think if you also explain the time complexity and space complexity of the final solution, it would be helpful.

[@jatinbhatoya8420]

leetcode 51 static List finalAns; public static List solveNQueens(int n) { int arr[][] = new int[n][n]; finalAns = new ArrayList(); printNQueens(arr, "", 0); return finalAns; } public static boolean isItSafePlaceForQueen(int arr[][], int row, int col) { // CHECK IN ABOVE COLUMNS for (int i = row - 1, j = col; i >= 0 && j >= 0; i--) { if (arr[i][j] == 1) return false; } // CHECK DIAGONALLY ON LEFT for (int i = row - 1, j = col - 1; i >= 0 && j >= 0; i--, j--) { if (arr[i][j] == 1) return false; } // CHECK DIAGONALLY ON RIGHT for (int i = row - 1, j = col + 1; i >= 0 && j < arr[0].length; i--, j++) { if (arr[i][j] == 1) return false; } return true; } public static void printNQueens(int arr[][], String qsf, int row) { if (row == arr.length) { // System.out.println(qsf); List ans = new ArrayList(); for (int i = 0; i < arr.length; i++) { String st=""; for (int j = 0; j < arr[0].length; j++) { if (arr[i][j] == 1) { st+="Q"; } else { st+="."; } } ans.add(st); } finalAns.add(ans); return ; } for (int i = 0; i < arr[0].length; i++) { if (isItSafePlaceForQueen(arr, row, i)) { arr[row][i] = 1; printNQueens(arr, qsf+row+" - "+i+" , ", row + 1); arr[row][i] = 0; } } }

[@SumitKumar-sx1oi]

for 3 output shouldn't be blank , output should be (0,0) -(1,2)

[@parasrawat9321]

i did it in c++ with my logic: #include #include #define max 100 using namespace std; int chess[max][max]={0}; bool saferow(int r, int c ,int n){ for(int i=0 ; i=0) { if(chess[r1][c1]==1) return false; c1--; r1--; } r1=r , c1=c; while(c1=0) { if(chess[r1][c1]==1) return false; c1++; r1--; } return true; } void queens(int r, int c, int n, string op) { if(r>=n) { cout

[@abhishekranjan1094]

Thank you so much sumit sir... #leetcode solution class Solution { List finalList ; public List solveNQueens(int n) { int[][] queen= new int[n][n] ; finalList=new ArrayList() ; printQueen(queen,0) ; return finalList ; } public void printQueen(int[][] queen , int row ){ if(row==queen.length){ List ans = new ArrayList() ; for(int i=0 ; i=0 ; i--, j--){ // left diagonal if(queen[i][j]==1){ return false ; } } return true ; } }

[@faizanhaider3953]

Sir mujhe to lagta h X academy aur bhi jo platform hai... Sb aap se parh k tahalKaa macha rahe honGai aur alag se jaa k phokat me u6al rahe hai 😂😂 BTW explanation is on Baap Level... Thanks q so much sir

[@gurpreetsodi3948]

I watched many videos, but for understanding code this is best.

[@prernnajain1532]

Sir I'm getting stack overflow error .. please help mee😭

[@lochan47]

10:30 I am just leaving the time stamp for myself, so other please ignore.

[@rithikraj1813]

But apne recursion pdhaya aacha h puri series follow krri but vo flood fill wala ghaph mei batana chahiye tha 1st yr wale darr jaayenge 😂😂

[@ShMayank]

Initially when the queens were placed randomly, I was a bit confused as to why it was being done but when the condition to check for safe place was added, it made so much sense and the solution became super easy. Can't thank this channel enough, really

[@kunalvaishnav9283]

thankyou no one explained recursive tree you are the first to explain in it thankyou so much

[@akshyananda7219]

Thank you Sir, Working on DS and Algo questions these days, your explanations to problem statements and codes help a lot.

[@Pepcoding]

Happy to help! If you like our efforts, will you like to write a few words about us here (www.quora.com/What-are-the-good-websites-to-learn-data-structures-and-algorithms ) Keep watching and keep loving Pepcoding😊

[@ashishgoswami6303]

Sir, I've seen Ur video where you asked people to not call you God. But each time a watch a video of yours it's the only thing that crosses my mind this person has godlike teaching skills unparalleled by any other person . This bootcamp will blow up to be India's finest very soon. I'm just happy I got the chance to study from you 😁

[@Pepcoding]

Wow, thank you

[@ExGoogleAmazon]

JAB KISI BHI VIDEO SE SAMAJH NHI ATA TO MAI IS CHANNELE PE ATA HU , ITNA EASY BATATE HAIN KI

[@TabrezAlikhan7960]

Sir yadi mare aap ka content complete kar liya to kite salary ka package lag satka he sir yah par Coching available nahi ye sir

[@rishabhgupta5460]

what is queen so far why we are passing it in printNQueen method anyone

[@AnjaliSingh-uq9fy]

superb explanation sir, its really helpful when u dry run the code multiple times, thank you for teaching us

[@yogeshedekar6078]

Sir really really good explanation. I think you should write a book explaining your methods. Your methods are so unique and easy to understand.

[@TansiBhandari]

Sir is there any paid DSA course of yours??

[@aashishgoyal1436]

Thanks a lot for such a valuable content

[@Pepcoding]

My pleasure

[@zeeshanalimannur5704]

it was fun understanding this problem

[@zeeshanalimannur5704]

it was fun understanding this problem

[@abhishekkumaryadav1928]

Amazing... Sir love you❤️❤️

[@AbhinavGupta3414]

Nice one. Have been revising it from 5 years. Don't think I will need to revisit the topic ever after. :)

[@Pepcoding]

Excellent! Keep learning, Keep growing and keep loving Pepcoding!😊

[@freelancedeveloper2591]

if you can tell the time complexity that will be very much benificial for us

[@Pepcoding]

Beta, I regret to inform you that, I won't be able to answer/solve the personal doubts of each and every student over here. For clearing your doubts, you can join our community on telegram - t.me/pepcoding.

[@freelancedeveloper2591]

@@Pepcoding i will definitely join it

[@_Burhan_Hilal_ECE_]

Sir i swear by God i searched for this problem on youtube and watched almost all the videos but could not understand the proper working of this problem/backtracking. U made it so easy that even a layman can understand. Seriously agar yaha sai nhi samjha toh kahi aur sai b nhi samjh pavo gai. I have watched other videos of u and the unique thing i noticed about you is u do the dry run of every problem. Really appreciate ur efforts sir. U made my day sir. 🥺🥺

[@info1.091]

Very nice teaching style great sir

[@adityapathak300]

Itna detail mai sb cheeze koi nhi samjhata Respect to you Sir!!

[@Pepcoding]

Hope you love the explanation, for better experience and well organised content visit - nados.io

[@TabrezAlikhan7960]

You DS and java ke King ho sir

[@raj_kundalia]

Watched on 22 Dec, 2021 - Thanks for the video.

[@Pepcoding]

Glad you liked it! Keep learning. And for better experience and well organised content visit nados.pepcoding.com

[@SCRIPTSAG]

Sit time complexity sir eski n*n se bhi jata hogi kya

[@Pepcoding]

n raise to power n beta

[@rithikraj1813]

Row wala case optimize kr skte h set use krke aur vaise bhi set ki atmost n hi hogi aur syed aur syed iss question ko aur bhi optimize krra jaa skta h kyun ki queen knight ki chaal nii chalti to agr 2 knight attacking position mei h to to vhi queen ka position hoga to dhaai dhaai ki call lgakr bhi syed krra jaa skta h....usme bas yeh check krna pdega ki koi bhi queen ek dusre ki row aur column mei nii honi chahiye....... aacha n queens place krni pdhi h na to yeh nii hoga kahe ki yeh 2 queens ki bhi solutions de dega to agr atmost n queen huaa to yeh solution de skte ho...syed...maybe....

[@exposevideo5787]

Sir 2 ka lea nahi sal ra ha

[@mdshaheerrafeeq2438]

Sir I have seen so many videos but your content is out standing , the way you teach line by line is awesome 😎.

[@Pepcoding]

I am glad you liked it. I also hope that you are watching till end and trying to understand the what, how and especially why of the problem. If you like our efforts, we request a review g.page/Pepcoding/review?rc You can subscribe to our channel here kzbin.infoabout?view_as=subscriber

[@arihantjain5869]

Sir jab hamara matrix size 3 ki hogi jab queen (0,0) and (1,2) pe place bhi to ho sakti hai. Please resolve my query.

[@harshitgoyal2382]

zindgi bhr aapka gulam bnne ko tyyar hai sir....

[@Pepcoding]

Hope you love the video! For better experience and well-arranged content visit- nados.pepcoding.com Don't forget to follow us on Instagram instagram.com/pepcoding/

[@HarshKumar-nh6be]

Sir fabulous teaching none of teachers was able to explain this problem....mind blowing sir..😎😎😎❤❤❤❤❤❤❤. KEEP IT UP SIR!

[@Pepcoding]

glad you liked it!! keep watching !!share among you peers

[@HarshKumar-nh6be]

@@Pepcoding why not? You are my best teacher😊

[@sushilvarande6223]

Finally understand the N-queen problem by watching a video once. Sir, you are great and thank you for your effort and great teaching.

[@Pepcoding]

Thankyou beta! I am glad you liked it. I hope that you are watching till the end and trying to understand what, how, and especially why of the problem. If you like our efforts, will you like to write a few words about us here (www.quora.com/What-are-the-good-websites-to-learn-data-structures-and-algorithms )

[@Anand14527]

Amazing explanation

[@ankoor]

Python code: 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) result.pop() self.board[row][col] = 0 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) output = b.nQueens() print(output)

[@binodkumarsingh1705]

What to say, Many thanks to Pepcoding you guys make coding simple... 😎

[@prachisingh5771]

well explained sir

[@yuvrajsubh6723]

Great explanation. Truly very helpful for me.

[@adarshsaraf9702]

sumeet sir is lord

[@ayushjain5360]

Awesome Explanation, Sir

[@Pepcoding]

Keep watching

[@loserfruit9663]

Thanku ❤️❤️

[@nidhirani8559]

One of the best explanation Sir... Mja aa gya..

[@RitikRaj-ze8xg]

Finally, crystal clear explanation, great work sir Ji 🔥🔥🔥🔥

[@Pepcoding]

Thankyou beta! I am glad you liked it. I hope that you are watching till the end and trying to understand what, how, and especially why of the problem. If you like our efforts, will you like to review us here - g.page/Pepcoding/review?rc

[@utkarshsharma1185]

Thanks

[@AyushKumar-fk5lm]

Gazab explanation! Itna achha koi nahi samjha sakta ye sawal!!

[@vaibhavpanvalkar3025]

best backtracking and N queen explanation ever.

[@danishrockz1]

pls try to categorize questions company wise

[@FirstLearningthanEarning]

for(int i = row, j = col - 1; j >= 0; j--){ if(chess[i][j] == 1){ return false; } } Sir horizontal check laga skte h kya

[@_Billa_007]

zaroorat hi nahi hai

[@0_0-0_0.]

Sir which software you use for drawing. It is good for us visualise or draw problem and algorithms before coding Please tell me🙏🏻🙏🏻

[@thexhist3609]

openboard

[@ProgrammingWithProject]

Sir you are the best teacher in the world 🌍

[@sakshiaggarwal6199]

khud se bhi dry run krke bhot acha samajh aya sir. Thank you so much !!

[@mindbodyps]

Only one ⭐ in whole youtube

[@Pepcoding]

Hope you love the explanation, for better experience and precisely organised content sign up on nados.io and start learning.

[@devanshpurwar]

maaja agya sir

[@girikgarg8]

Done!

[@kasturisanyal6649]

This was such a great explanation. No doubt you are the best recursion teacher. Thank you so much for this detailed explanation. you made sure that every student understand the logic ! Keep uploading such great videos:)

[@Pepcoding]

Keep learning and keep motivating. For more such exciting content, don't forget to visit nados.pepcoding.com

[@Arun-ue4co]

Sir what is the time and space complexity?

[@Pepcoding]

kaun program kitna time lega, kitni memory khaega. aur input ka size badhega to time aur memory kaise badhega ye analysis karna.

[@anjneykumarsingh4461]

String aur time complexity dal dijiye ye sb bhut hard h

[@deepakojha3216]

@@anjneykumarsingh4461 Bhai space-time complexity pe @pepcoding wale na Dalen to thats best kyunki en topics pe time waste hi hota h ....tum ye sab 1/2 hour me samajh jaoge google KR lo ....but bro salute to @pepcoding for valuable content...

[@anjneykumarsingh4461]

Yes bro i have done it see it's 1month old comment, I use to cry with recursion it's like God gift apoorva di told me about sir

[@sakshamsrivastava6280]

most beautiful video on the this topic

[@abhishek5966]

sir please provide us a video of graph colouring and practice of some questions on it .

[@Pepcoding]

Yes, this will be covered in level2

[@abhishek5966]

sir i will put all my suggested topics here which i will find hard to understand and which others have also not covered very well ..as it will help us .If you feel my suggestions are good then please also make videos on those topics . currently---FLUERY'S ALGORITHM and other important algos and methods to detect euler circuit

[@Pepcoding]

@@abhishek5966 beta kra dunga. level2 ke baad level3 mei jo kahoge use treat kar dunga.

[@DivyaPrakash-bj6zk]

I will definitely crack my dream company and all credit goes to Sumeeet Sir ❤❤❤❤

[@Pepcoding]

Keep it up. For better experience and well organised content visit - nados.pepcoding.com

[@deeksha6514]

Super awesome explanation! Sir

[@anmoldogra5150]

Sir is question ko seedha krnesolve Kiya toh nhi BNA pr pr thodi Der video Dekh k approach samaz as gyi..sir khud se Kaise bnaye ya time k Saath Saath problem krte aa Jayega ...bdiaya smzaya sir Aapne🔥🔥

[@Pepcoding]

Thankyou beta! Keep learning and keep loving Pepcoding

[@ankushsaini2068]

👍✌

[@sanketsinha9816]

Sir question ka solution dekhna pr rha ha but ek bar dekhne k bad me clear ho jata .. khud se kaise bnaye sir kya time k sath problem solve krte aa jaega ? Btw Love your teaching Style sir

[@Pepcoding]

beta ye to time ke sath he hota hai. jab 1000 question solve kar loge to thought process ban chuka hoga

[@AshishGusain17]

thanks for the video

[@Pepcoding]

Glad to know, that you love the explanation, for better experience and precisely arranged videos. Visit - nados.pepcoding.com and sign up to NADOS. Don't forget to follow us on Instagram instagram.com/pepcoding/

[@vihaansingla5088]

Sir questions kudh nhi bante Solution dekhna padta hai sir please help

[@Pepcoding]

beta ye normal hai. 1000 questions kar lo. try -> watch -> solve mode mei. uske baad watch ki jarurat nahi pda karegi.

[@vihaansingla5088]

@@Pepcoding thank you sir i like your videos and services

[@anjneykumarsingh4461]

Bhai kisi se nhi hote jee main k question direct thori solve hojate the

[@learn_with_yourself]

great man!! lot of love to your dedication

[@SCRIPTSAG]

Sir esme base jo hai wo sirf answer print kerne ke liye lgaya hai uske bad return ker diya hai taki wo jha se aya hai wo next pe check ker sake ki koi aur to nhi hai na

[@Pepcoding]

ji sahi baat

[@pranavvyas7218]

has anyone tried this question in c++ with the approach that sir has taught ?

[@piyushparadkar6290]

I did Cant understand why solution is coming wrong answer for 4 is same as written but after submiting its showing wrong answer even i cross checked 4 times.

[@vidyabhushan7655]

Amazing explanation!

[@ruirui7344]

thanks, sir for your effort.

[@abhishekranjan1094]

Sir why its not working for output 2 and 3 😊🙌

[@utkarshpant5297]

Because there is no way you can put N queens in every row for 2x2 or 3x3 board

[@rahulnaraniya1222]

love pepcoding!

[@amanpreetsinghsetia1524]

Amazing Explanation sir !

[@adityasrivastava7956]

great!!

[@adityasrivastava7956]

sure sir!