Lecture 65: Binary Tree FAANG Interview Questions || Part-3

[@GaneshBhutekar-nu1gd]

"himmat chahiye yaha tak dekhne ke liye " -> this make me more motivated bhaiya thanks

[@heerathakur2680]

Honestly speaking, I think you are the only one who has made these kind of crisp and to the point videos by covering all the topics on binary trees. Thank You

[@sambhavsharma2780]

Sir in k Sum Path question there is no need to pop_back from path vector because in every auxiliary stack call path vector having a different memory because we passes as a call by value. pop_back() function is needed when we do call by reference like vector &path.

[@oniii-chan_]

29:35 Problem in the question in K sum path is that the complexity of our code is O(N^2) but expected is O(N)

[@34-devendrasinghit18]

here we have used map and optimised it. class Solution { public: #define ll long long map mp; int ans=0; void solve(TreeNode* root, int targetSum,ll currSum){ if(root==NULL) return; currSum+=root->val; ans+=mp[currSum-targetSum];//it mean between the ongoing process there is a place where targetSum is generated. mp[currSum]++; solve(root->left , targetSum,currSum); solve(root->right , targetSum,currSum); mp[currSum]--; currSum-=root->val; } int pathSum(TreeNode* root, int targetSum) { mp[0]++; ll currSum=0; solve(root,targetSum,currSum); return ans; } };

[@amitprakhar4802]

@@34-devendrasinghit18 bhaiya wala code to gfg pe run hogya but hmare me nhi ho rha

[@shashankjangir1873]

@@amitprakhar4802 bhaiya ke computer pe jake ke kr run

[@amitprakhar4802]

@@shashankjangir1873 tune wahii kiya tha kya 🤣🤣

[@mr.dependable4885]

@@amitprakhar4802 testcase update hue hai uske

[@Singh11225]

Binary trees are my fav data structures. Didn't get any question related to it ever in an interview but I enjoyed these questions the most when I was preparing.

[@divyareddy7622]

Divya Reddy 1 second ago did you complete kth ancestor in a tree problem using the vector which was given as homework? this code is not working :( int kthAncestorsol(Node *root, int k, int node, vector &path) { if(root == NULL) return 0; path.push_back(root->data); if(root->data == node) { for(int i =0; ileft, k, node, path); kthAncestorsol(root->right, k, node, path); } int kthAncestor(Node *root, int k, int node) { vector solu; kthAncestorsol(root, k, node, solu); }

[@ashishpal5088]

Bhai java vala koi hai other ancestor ka question Mahi ho Raha hai

[@deveshbisht926]

@@divyareddy7622 try this int solve(Node* root, int k, int node, vector& path){ if(root == NULL) return 0; path.push_back(root->data); solve(root->left, k, node, path); solve(root->right, k, node, path); int size = path.size(); for(int i=size-1;i>=0;i--){ if(path[i] == node){ int index = i-k; if(index

[@titaniumcoders6710]

@@deveshbisht926 😀

[@namanjain7949]

run time error ! @@deveshbisht926

[@RishiRajVishwakarma-le7xv]

Not Just DSA but this playlist is also teaching me consistency and kind of attitude that is required to crack some major companies.

[@adityakishore5946]

Can someone tell me the case where the value of k becomes less than 0 in the Kth Ancestor in a Tree problem.

[@rickseth9207]

@@adityakishore5946 can you be more specific?

[@rickseth9207]

@@adityakishore5946 just a matter of coding style you can actually just write k==0 and the code would work just fine.

[@akashpartel7391]

@@adityakishore5946 the value of k can not be less than 1, let alone 0. what do you say the 0th ancestor of a node is? the counting starts from 1; 1st ancestor: just above it; 2nd ancestor: two level above it; and so on.

[@aishwaryaporwal2321]

No words can define ur consistency n efforts ... Thank you so much♥️💯💯

[@17_sidhantbahri66]

paid comment

[@aishwaryaporwal2321]

@@17_sidhantbahri66 okk then u can pay me?? 😂😂

[@mansoorrr9167]

@@17_sidhantbahri66 sharam Karo itni mehnat karke free se first class se padarahe bhaiyya aur tum jaise log aisa comment Karthee ho

[@rickseth9207]

@@17_sidhantbahri66 Indians really know how to kill some person's spirit, chalo maan bhi liya paid hai toh kya? tum tareef na karke agar burai he karoge toh iss situation mai atleast paid comments tareef toh karenge

[@vmstudy9965]

Koi dekhta ni h yha Tak. Mehnat lgti h yha tk tikne k liye. Sir ekdm right baat kahi aapne❤

[@hritiksingh9873]

instead of putting if(k

[@vikasjat1170]

No bro, all test cases are not passing

[@supersuperhero2449]

​@@vikasjat1170my all case passed by this, k==0 , and then simpy return root

[@stevebucknor7058]

Well, that is what i did

[@vakeelsaab5485]

@@vikasjat1170 Node* solve(Node *root, int& k, int node) { if(root==NULL) return NULL; if(root->data==node) return root; Node*leftans=solve(root->left,k,node); Node*rightans=solve(root->right,k,node); if(leftans!=NULL && rightans==NULL) { k--; if(k==0) { return root; } return leftans; } if (leftans==NULL && rightans!=NULL) { k--; if(k==0) { return root; } return rightans; } return NULL; } int kthAncestor(Node *root, int k, int node) { Node*ans=solve(root,k,node); if(ans==NULL || k>0) return -1; else return ans->data; } This code works perfectly for all test cases there is no need to changing k to INT_MAX

[@janvisharma2377]

great video , I learned a lot from your lectures thank you very much for that much efforts ❤❤

[@srajittanwar636]

Thank you so much for increasing the number of questions. Itna jaldi toh koi paid course me bhi respond nhi krta

[@shashanksingh4968]

Wish peeps like you were there when we started college back in '16. We never wrote a line of code for tree and other advanced topics, we studied theory. Now working in service based company, with goal to work in PBC soon, you came as messiah, no amount of words will be enough to thank you. ❤❤❤

[@ajayjaadu42]

,,,

[@alexrcrew1975]

bro where u work at present?

[@SaurabhKumar-vr3xc]

bhaiya , is important to lock k. we can also do it by doing if(k==0) { return root; } if any of one(leftans or rightans) is not NULL because we are not going to increase K again when K touches 0.

[@shubhamshah9837]

Best playlist for DSA!! Thank you so much for this❤❤

[@AdityaKumar-tb9he]

man kre to krna na kre to mt krna are kaahe nhi krega aap pada hi itna badiya rhe ho thanku bhaiya ji

[@AbhishekGupta-cg2vj]

No words can define ur consistency n efforts ... Thank you so much

[@thecrazyfilmygyan550]

honestly sir u are the reason who made the DSA easy

[@kritarthtripathi9793]

Consistency and content is on next level...THANK U SO MUCH❤

[@shriRam.312]

thankyou so much bhaiya You are only one person who honestly teaching every topic with full effort like dry run and many more thank you🙏🙏🙏🙏🙏🙏

[@rohitsingh5955]

Great Work ! , just one thing in Que 3. path.pop_back() is not required since we are not passing it by reference . Added element will get removed automatically going back up the tree.

[@shivamsehrawat7610]

It's mutable unlike strings and int so its required I think

[@shubhammittal5342]

@@shivamsehrawat7610 no bro its not req only if we pass by ref then we had to manually pop it

[@sagarsen5856]

Isn't an array is always passed by reference

[@worldfromhome4033]

I don't get one thing....how is the code working without passing it by reference??

[@prashantMishra-it2im]

True

[@thisismr900]

im confident enough now with these trees. Just mentioning for solving LCA it took 27min.12s to complete it by myself totally. Thank you for all teachings. and transforming lallus to shers

[@rakhshanahmad8057]

Love the step-by-step approach you take in your lectures - it makes the concepts easier to grasp. Thanks for the helpful explanation of the concept.❤

[@SHAKIBANSARI893]

"Banda Raat Raat Bhar Jagta Hai ", Heart touching movement❣❣❣❣

[@PrashantSinghRajawat22]

Day 61 and lecture 65 .. consistently, I'm watching your videos. A great thanks to you Bhaiya for this course ...Bhaiya your consistency inspires me to be consistent and don't give up ..

[@utkarshtipre7121]

itna detail solution batane wala ek hi banda hai,....love bhai.

[@riyajain3655]

Great video!, also one thing you dont need to call pop_back function on path vector in K Sum Paths question as vector is called by value so it wont bother Thanks for making a great course for free

[@amarnathprajapati2543]

Sir, आपके निस्वार्थ मेहनत के आगे मै शब्दहीन हो गया हूँ।।

[@shreyagupta2282]

I was never able to do tree problems but by watching last three videos of tree questions you have made my concepts clear to a great extent...Thank you sm for your efforts 🤗❤.....Please make us understand all questions of Dp and graph also so easily😂🙏🏻

[@divyareddy7622]

Divya Reddy 1 second ago did you complete kth ancestor in a tree problem using the vector which was given as homework? this code is not working :( int kthAncestorsol(Node *root, int k, int node, vector &path) { if(root == NULL) return 0; path.push_back(root->data); if(root->data == node) { for(int i =0; ileft, k, node, path); kthAncestorsol(root->right, k, node, path); } int kthAncestor(Node *root, int k, int node) { vector solu; kthAncestorsol(root, k, node, solu); }

[@torus151]

@@divyareddy7622 you have made mistake......the if condition in recusrion function should be bellow the left and right call...hope u got it

[@divyareddy7622]

@@torus151 no I tried it's not working even after that

[@dep2460]

@@divyareddy7622 your kth ancestor fxn has return type int ,so when calling left part and right part it will return some value, based on that it will have multiple cases . So I would suggest it make Node * return type and check ancestor in main function by traveling your vector. If not understood I will send the code.

[@shubhamkathiriya3830]

appriciate your efforts!! job + video recording + finding the best content and questions and all these in free hats off!!

[@Profnegi]

last tak dekha full samaj aaya sai me kamal ho gya bhaiya bs ye hai ki merko abhi code dhang se bnana nahi aata but i know practice ke bad pkka bna llunga mai thx.........................................................................

[@gargkapil]

Best learning series on KZbin. Because of this series, I am fully motivated to learn it completely.

[@akkadBakkad_BambeBo]

bhaiya, i am watching this playlist offline as internet is not readily available. And everywhere around me when i hear word DSA, everyone talks about your playlist. Thanks for this playlist. It's very helpful.

[@programmercoder3000]

In kth ancestor problem, there is no need to lock the answer by doing k=INT_MAX, we can just change the if condition to k==0

[@mukib_khan_]

does it give correct output for all cases?

[@udaytewary3809]

really thankyou bhaiya apki wajah in sb topic me dhire dhire confidence aa rha h

[@therealartist9]

bhaiya pls give dry run dont go so fast just by writing the codes only

[@KRISHNANANDMISHRA-b6y]

first question easy approch int maxsum = 0; int maxheight = 0; void solve(Node* root, int sum , int height ){ //base case if(root == NULL){ return; }//firstly we store sum variable sum = sum + root->data; if(height>= maxheight){ maxheight = height; maxsum = sum; } solve(root->left,sum,height+1); solve(root->right,sum,height+1); } int sumOfLongRootToLeafPath(Node *root) { solve(root,0,0); return maxsum;

[@imamamr]

In question 3 its given that we need to return ans modulo 10^9 +7 as the count can be very large.

[@govindsuryavanshi6653]

First I have completed all DSA series and now conclude this is Greatest ever DSA series to exist on youtube or paid courses. Your contribution will be remembered. You're God of DSA for us🙇‍♂ Thanks you.

[@Kishan_Kumar_14]

Learning Dsa from your series sir. It's great help for student community who's desired to learn coding & Dsa. It's have been 2 year of this series. But still no one have taught dsa with such a great explaination. Thnq love babbar bhaiya❤

[@noumankhan7662]

Best playlist for DSA ever seen😇

[@mayankuniyal4660]

If i have upskilled myself in DSA is just because of this man...Lots of respect sir

[@luckydewangan5985]

It took me 3hours for understanding every questions with codes and taking notes. Finally heading to next video. Thankyou so much bhaiya for such hard efforts and high quality content.

[@snipper6683]

bhaiya harr video k=last tak dekhta hu and majaa bohot ara hai ; god bless u

[@suvigyabasnotra7378]

Even DJ couldn't stop your consistency!

[@its_nawed4611]

I have no words to praise your efforts to teach us bhaiya ...❤Thankyou so much ...and han samjh me aa rha hai bhot achhe se

[@vaishnavrushikesh4022]

Really good content. Very good explanation and consistency. I really like this course. Thank you love babbar.

[@AyushGupta-ji5xp]

your explaination of every approach is the best part of this playlist

[@ChiragVashisthaBEC]

literally thank you for all the hard work you have put into making these videos, people like you have been empowering the youth of India to upskill and get placement, this empowerment means everything for students like me to gain a sense of direction in a tuff question to ask my self will it all be worth one day?

[@JatinKumar-w7f]

As per my observation, you have to add " return ;" in the end of solve function of finding k sum path, because without it , it becomes hard to return from recursion and the time complexity of your code is O(n^2),

[@rishabhkesarwani9506]

best teacher ever on DSA, and the best part is approach( algo making) thanks a lot bhaiya.

[@divyagupta6854]

I watched all the three parts of this FAANG interview question series. Shuru mein laga tha ki pata nahi complete kar paunga ki nahi poore videos, par har video ko end tak dekha, samay laga thoda, par worth it tha totally. Keep bringing us such helpful series Babbar. Hats off!

[@SakshamPanpaliya]

The amount of respect you deserve is out of this world!! Heads up to your hardwork.

[@KeshavAgarwal-ix6qx]

Great appreciation for your work sir!

[@asifmondal7609]

I'm greatly proud on my real teacher sir ‼️😊 Keep growing and keep teaching us ♥️

[@harshpandey4190]

Thankyou So Much, Confidence is Increasing day by day

[@satyamupadhyay8326]

Following your course since last month and it's been an amazing journey till now.......learning new ways to solve a problem. Thanks a lot for your consistency, seeing you being consistent makes me get up and do the hustle.

[@ashishkundara-8355]

hardwork ko salam sir....

[@CuriousNagpal]

Thank you for the amazing content on DSA. I think this is my 27th video in the last 4 days. I have my Google interview in the next couple of days. Will definitely post back about how it goes. And if I am successful in cracking it, you are going to be a very big reason for it! Thanks again for spending so much time and helping me out❤

[@mohdkhaleeq7468]

Is google currently hiring for sde 1 fresher

[@SACHINPCE22CY051]

Bhaiya aapki mehnat kitni years tak kaam aarhi hia aur aati rhegi ... the best explaination ever ..... really very premium content ans easiest explaination ...... i am following this series from 1st of vedio and its superb .... thanx bhaiya for this

[@suvigyabasnotra7378]

Hum bhi aapki tarah Mehnat maar rahe hain. Got to sleep only 3.5 hrs in the last week. And colleges are about to open physically next month, so here's hoping most of this course gets covered before that, so we wouldn't need to bear further time crunch.

[@shivakashyap5017]

one of the best DSA course on youtube, thanku very much bhaiya❤❤ for providing us this for free

[@sahilpanchasara]

Le other paid DSA courses: we have best resources. Le Love Bhaiya: Hum bhi bana lenge vobhi free me 🔥🔥🔥🔥🔥

[@vishakhaborkar6336]

but ab to paid kardiya bhaiyane

[@KunalKumar-tp1cc]

Q4. can be done in kinda similar way in which bhaiya did but without ans locking... bool solve(Node *root,int &k, int node,int &ans){ if(root == NULL) return false; if(root->data == node) return true; bool left = solve(root->left,k,node,ans); bool right = solve(root->right, k,node,ans); if(left||right){ k--; if(k==0) ans = root->data; return true; } return false; } int kthAncestor(Node *root, int k, int node) { int ans; solve(root,k,node,ans); if(k>0) return -1; // If k is greater than required distance b/w nodes. return ans; }

[@shubhampatel_2745]

Good approach really appreciate you

[@ravipandya7411]

for K sum path : Mistake: TC can not be O(N). TC will be O(N * No. of nodes in vector)

[@prayagpatel9136]

and also path.pop_back(); is not required.

[@divyareddy7622]

did you complete kth ancestor in a tree problem using the vector which was given as homework? this code is not working :( int kthAncestorsol(Node *root, int k, int node, vector &path) { if(root == NULL) return 0; path.push_back(root->data); if(root->data == node) { for(int i =0; ileft, k, node, path); kthAncestorsol(root->right, k, node, path); } int kthAncestor(Node *root, int k, int node) { vector solu; kthAncestorsol(root, k, node, solu); }

[@vaibhavdhiman1690]

@@divyareddy7622 int solve(Node *root, int k, int node, vector &path){ // base case if(root == NULL) return 0; // if node found if(root->data == node) return node; path.push_back(root->data); // traverse int left = solve(root->left, k, node, path); int right = solve(root->right, k, node, path); if(left == node){ return left; } else if(right == node){ return right; } else if(left != node){ path.pop_back(); return 0; } else if(right != node){ path.pop_back(); return 0; } } int kthAncestor(Node *root, int k, int node) { vector path; solve(root, k, node, path); int response = -1; int size = path.size(); for(int idx = 0; idx

[@saurabhrthakur]

@@vaibhavdhiman1690 thanks brother.

[@succesmantramotivational8795]

because we are poping back while returning and upar se atte vakt N times and return vector ke through ja rhe hain toh toh jitne baar pop krr rhe hain utne baar vector count ho rha hain

[@theelysianone6033]

lovely explanation sir, highly appreciated that you're teaching in such detail for free...

[@adityagosavi8186]

For K sum question, there is no need to pop the element after each call, because we dont use path vector by reference here in the solve() function.

[@arthurlewin1952]

Do you think after we have found sum== k the loop should break

[@praveennemagoudar3442]

I gained confidence in thinking recursively. Thank you Bhaiya. Everyone should draw recursion tree and understand the flow. Then it becomes easy to write code.

[@deepakgoyal1643]

Homework - find kth ancestor by using vector Node* solve(Node* root, int k, int node, vector& path, int &ans){ if(root == NULL) return NULL; path.push_back(root->data); if(root -> data == node) return root ; Node* left= solve(root->left, k, node, path, ans); Node* right= solve(root->right, k, node, path, ans); if(left !=NULL || right !=NULL){ int size = path.size(); for(int i=0;i

[@ananyapandey8162]

bhai solution bhut achi tarah likha hai

[@faizannabi4824]

Thanks for making these videos free and putting so much effort into these losing your sleep.

[@swapnilsalunke5942]

The best teachers teach from the heart. Thank you for all that you do!

[@jatinnirwan812]

Finally uderstood Binary Tree thank you for easily explaining complex question

[@yayyayayy]

Thank you so much for this course!! This is much much more than paid coursesssss

[@inter3988]

I just completed the video in 3 hours. Great work. The codes are so much fun

[@vanshitamishra4964]

aapki mehnat dekh k hum mehnat kar rhe hai bhaiyya, you're the best.

[@ananyakhandelwal4051]

None of the biggest KZbin channel can provide this type of quality content, teaching so nicely without even having experience in teaching.

[@prabhatdwivedi4141]

last k 30 second dekh k aaj pta ni kyu emotional feel hua love you bhaiya

[@SovanMajumder]

learning late but learning is great with you... Bhaia really you are my motivation. When I feel sleepy I just watch the last part of your videos.

[@abdulhaadi8178]

Always watch till very end ... Watching this to the point U said "99% bhag jty hon gy yhn tk"

[@shismomin1172]

This is one of the best course for beginners to learn DSA

[@vishalgarna4580]

You are a great power to become future of students big heart ❣️❣️❣️😊😊😊

[@chiragyadav5467]

east or west , love bhaiya is the best and teaching method is super best

[@freefiregamers1345]

Two words for you is The Best Teacher.....................................................

[@AnitaBarkhane-c9i]

LOVE BABBAR IS BEST , Bhai understood hai sab and main thing is that he is teaching us in hindi.

[@vanshikasoni6950]

Big salute to creators like you 🙏🙏

[@ratneshsingh8403]

No words for you bhaiya, you make me fall in love with DSA, Thts why you are the king of DSA, God of DSA.

[@RohanKumar-nt7xq]

One of the best course of DSA on KZbin .

[@AnilKumarPatidar11]

To be honest, this Tree series is very good bhaiyya, and if I listen to your voice, things get automatically. very very Thanks bhaiyya.😊

[@CollegeInsightsUnlocked]

love the way u explain each and every concept in a detailed manner.

[@keshavgarg8554]

Bhahiya I can Comment thousand times, the way you have taught is just fabulous. Respect your hard work!! Again, Thanks for these fantastic lectures!

[@AmanBansal-h2k]

Thankyou so much bhaiya, I understand everything of this lecture 😊

[@suplavpandey8345]

sir we are enjoying the way you taught all topics . Thank you sir .

[@aayushsaxena7982]

Your teaching is superb Learned DSA because of you only

[@beastndvk2003]

Best explanation sir ...every concept is crystal clear

[@piyushsonigara5550]

59:00 Nahi bhagenge pura dekhenge VAMOS! 🔥🔥🔥 Kya question karwaye hai , quantity + quality dono hai unreal man.

[@vishwasverma4422]

thank you so much bhaiya for adding huge values to our lives both academically and humanely!

[@harshalpatil6482]

K Sum paths time complexity is O(N*H) where H stands for height

[@jaikhatri4783]

Bhaiya thank you problem solving skills bhi better ho rahi hai main bhi apke sath solution soch pata hu

[@iconic7357]

problem in the path sum iii question is our code's time complexity is o(N^2) but expected is o(N)

[@shubhamshah9837]

Thank you bhaiya , the way you explain every question is awesome , you are the best tutor, 🔥🔥

[@apurav363]

Great job sir, kafi achhe se samjhaya aapne thankyou