Learn the basics of trees, data structures. This video is a part of HackerRank's Cracking The Coding Interview Tutorial with Gayle Laakmann McDowell. www.hackerrank....
be careful tho. A lot of people overuse recursion because they wanna be fancy. But remember, recursion builds a stack in memory and does not release it until it works it's way back to the first call. This could lead to some issues. Most things that people use recursion for can be easily done with a simple loop.
Very well explained. I found how you visually grouped the "paths" of recursive calls helpful to understand what was happening when "traversing" the tree.
Thanks for the video. But IMO there is an issue with how the code is written since these methods are operations on the tree data structure, not the node data structure, hence they should be located inside the respective ADT. Apart from that, the code looks great and is easy to understand. Great work!
@kicksomeup6998 you mean that each individual node does not contain a node data instance variable? Or that the contains() method is not written as an instance non static method within the node class?
Very excellent explanation, clearest one I’ve ever heard. Deleting needs its own video, so I understand why you decided not to include it. On programming tests, I’m always like “can I not write out all the recursion methods? I hate writing all the if statements... we both know what we are talking about, this is a binary search tree ok?” haha.
I would have expected the insert and contains functions to be in a Tree class of some sort, and the node to be an internal implementation operating on a comparable interface. So we can return just the data not the node itself. I know it's outside of the scope of this video, but wondering if it's a common practice to put this logic inside of the node class.
it is called as, public static void main(String[] args) { //Say you have a tree with root node being "root" int value = 6; if(root!=null) { root.insert(value); } }
C# people who copied this and don't get it please read. First, do everything she does in this video exactly the way she did it. It literally works exactly the same in C#. Only difference, also add an empty constructor that takes in no argument. "Public Node( )" This will let you instantiate the node class in your code, without first inserting a value, so "Node testNode = new Node( ). Then create an int[ ] "int array or list whatever" and fill it with a bunch of misordered numbers. Then run a foreach loop filling taking each value from the array and plugging it into the node you created. "testNode.Insert(value)". Then you're good to go. Afterwords you can run the testNode.printInOrder and actually see that it worked. Good luck!!! Reply back if you didn't understand.
I was confused as to how 10 gets printed before 5,8. But it's more like, if root has something then do printInOrder of left & 'AFTER' left.printInOrder (which is recursive in itself). print the node itself. So basically the ENTIRE tree on the left of every node gets printed first...Then the root of every subtree, then then the right and finally the ENTIRE subtree of the right
She always have to bash that she is the author of Cracking the Coding Interview. I know it woman. I have watched tons of your videos. Edit: I love your videos
I hope you can post a video on how to build a relatively balanced tree. With the example on this video, all the weight goes to the right side of tree. Like you said in the video is not very efficient.
Very nice little lecture, but I cannot figure it out which would be an example of a good real developer scenario in which a tree would be the more efficient way.
I love this explanation, but I’m kind of surprised that you had all of the BST methods in the Node class. It works, I guess, but just seems like an inappropriate place to put them.
2 Questions: method printInOrder() what is System.out.printIn(data) doing? Also in this in-order example.. why after 5 is the next “in-order” number 8? Shouldn’t it be 10? I understand recursively we’re traversing to the Left most depth node in the binary tree ( up until left == null ) - but I’m confused how we’re printing from that point forward.
I think this is cleaner... but is it better/worse? (Its C++, if any wonder) bool contains(int value){ if(this == nullptr) return false; else if(value == data) return true; else if(valuecontains(value); else if(value>data) return right->contains(value); return false; }
Honestly, after watching this video I got confused. I am sure that this code works fine, but why is there no Binary Tree structure being created? All the functions which ideally should be written for a BST data structure are written for a node. So if I wanted to construct a BST, do I create a Node object??
Finally someone who explains a concept without unnecessarily complicating it thank you
daaaaaaaaaaaaaaaaa!
Log sum * COS
simp XX
∪
2020 but, this playlist saving lives
It was made only 4 years ago...
Tree saves lives
Indian Lives Matter
2021
@@SlavaCh all lives matters
Gayle is a living legend ! Makes data structures and algorithm a doddle. Thanks Gayle. 😘
She just goes through the recursion in a very light way with good animation tool. Loved it. Thanks!
Your data structures videos are so helpful! You’re really good at explaining them quickly
This was the best Tree DS explanation I have watched. She’s amazing!
Very well explained code. Trees always give me problems when asked in tests.
Lol
I've created a JavaFX App that animates a Binary Tree from an array and this video solved most of my problems. Thank you so much!
in 2021 and this is still the most simple and well explained version. Thanks Gayle
This video was so beautifully explained, it's no wonder my lecturer recommended it. Thank you very much for your video.
Recursion is such a powerful tool!
It is until ..... stack overflow
be careful tho. A lot of people overuse recursion because they wanna be fancy. But remember, recursion builds a stack in memory and does not release it until it works it's way back to the first call. This could lead to some issues. Most things that people use recursion for can be easily done with a simple loop.
only when you have few data otherwise you'll have to use alternatives like dynamic programming
and such a exhausting struggle for the stack
@@shellgecko dafuq are you talking dynamic programming for stack?
saved me thousands of hours to understand this
thank you sooo much
very professional explanation
Never knew HackerRank had a youtube channel, the explanations are so good. Thank you for making these!!!
At least you found out 8 months ago, I just found out now
@@Wiseman_RSA Atleast u found out 3 years ago..
Jeez what more could you ask for. Clear, concise, and straight to the point
Best run down of trees I've seen. Code with examples after is very effective.
Very well explained. I found how you visually grouped the "paths" of recursive calls helpful to understand what was happening when "traversing" the tree.
3 years later and this playlist still getting people jobs😎
which playlist?
She is literally amazing !
Thanks for the video. But IMO there is an issue with how the code is written since these methods are operations on the tree data structure, not the node data structure, hence they should be located inside the respective ADT. Apart from that, the code looks great and is easy to understand. Great work!
That's what I thought too. It really confused me in the beginning till I realized it's not really a code for a node but for a binary search tree.
@kicksomeup6998 you mean that each individual node does not contain a node data instance variable? Or that the contains() method is not written as an instance non static method within the node class?
In the insert method it would not be val = data
Mind-blowing yet extremely simple recursive implementation!
Wow, this was precise, easy to follow and I feel I understood what is going on
Really great stuff!
Thank you, finally someone who doesn't take an hour to explain a 5 minute topic
Did she just pull a recursion and I understood it? Damn she's great!
she is so talented! Learned this right away thanks to her
this is AMAZING!! Well explained!
I watched this video and programmed binary tree in python totally it took me 30 mins... Professor could not explain in whole semester: D
Really crisp , clear and easy explanation. DS became so easy to grasp the way you explained.
Good stuff! Makes me feel dumb when the teacher says "Let's implement this. It's really simple."
Very excellent explanation, clearest one I’ve ever heard. Deleting needs its own video, so I understand why you decided not to include it. On programming tests, I’m always like “can I not write out all the recursion methods? I hate writing all the if statements... we both know what we are talking about, this is a binary search tree ok?” haha.
This is gold!! Everything made sense now!
I would have expected the insert and contains functions to be in a Tree class of some sort, and the node to be an internal implementation operating on a comparable interface. So we can return just the data not the node itself.
I know it's outside of the scope of this video, but wondering if it's a common practice to put this logic inside of the node class.
For the insertion. You have to Check if there’s a root node first of, I think. If data == null, then value = data;
it is called as,
public static void main(String[] args) {
//Say you have a tree with root node being "root"
int value = 6;
if(root!=null) {
root.insert(value);
}
}
I love the presentation of code alongside diagrams as im a visual learner, really appreciate it.
Thank you so much for the explanation!
This was a really clear explanation. Thank you!
Wow! Thank you so much for explaining this, I get it now. Now I just have to practice it.
I love your videos so much, keep it up, you are one of the best
short and on point that's wat I wanted.saved my time! thanks.
Finally, someone who write 5 the same way I do!
looks like an "s" ffs
There are dozens of us!
Thank you very madam. you have explained the Basics of tree traversal very nicely in a simple way..
I think you should have implemented contains method in the Binary Tree class instead of the Node class
Really Great Video and Explanations within short minutes which we can understand the concept. Kudos!! Team.
Thank you for this vivid walkthrough of the code. This is one of the best of this kind
This was such an easy to understand video. Does anyone know if Gayle Laakmann McDowell has her own channel?
Very informative and straight-forward video, thank you!
Very clear explanation and simple understandable code, Thanks a lot
WOW.... she explained it very well. Once you understand it... it's basically like elementary.
You made it very easy to understand. How simple it is and I always fear with the name trees.
C# people who copied this and don't get it please read. First, do everything she does in this video exactly the way she did it. It literally works exactly the same in C#. Only difference, also add an empty constructor that takes in no argument. "Public Node( )" This will let you instantiate the node class in your code, without first inserting a value, so "Node testNode = new Node( ). Then create an int[ ] "int array or list whatever" and fill it with a bunch of misordered numbers. Then run a foreach loop filling taking each value from the array and plugging it into the node you created. "testNode.Insert(value)". Then you're good to go. Afterwords you can run the testNode.printInOrder and actually see that it worked. Good luck!!! Reply back if you didn't understand.
I haven't touched C# yet, only Java. Why C# needs an empty constructor besides any given alternative?
More than amazing. Such a simple explanation. Well taught. Thanks HackerRank...
I was confused as to how 10 gets printed before 5,8.
But it's more like, if root has something then do printInOrder of left & 'AFTER' left.printInOrder (which is recursive in itself). print the node itself. So basically the ENTIRE tree on the left of every node gets printed first...Then the root of every subtree, then then the right and finally the ENTIRE subtree of the right
i understand your teachings better than my prof. nice video!💜
it's really helpful you are like saving lives appreciate it. thanks ma'am.
She always have to bash that she is the author of Cracking the Coding Interview. I know it woman. I have watched tons of your videos.
Edit: I love your videos
It is the first time I watch her, so I didn’t know that...
Wow. The way you explained it, beautiful!
She explained this 100x better than my professor could
Excellent explanation !! I can tell you, you have done excellent work, simple clear, and concise well done !! and thank you !!
Such an amazing explanation!!! Thanks for your video
One such algorithm (2:40 of clip) is the AVL Search Tree, where it prevents the skewed linked list Big O performance issue.
2:46 Candidate: these algorithms can be very complicated, so we are not going into details here.
Interviewer: Understandable, have a good day.
this was so well explained and clear! thank you!
what a coding skills mam just awesome '
Ohh my God what a simple expression u are Wonderfull teacher
I hope you can post a video on how to build a relatively balanced tree. With the example on this video, all the weight goes to the right side of tree. Like you said in the video is not very efficient.
wow this was pretty simple explanation and easy to understan thanks
Amazing explanation!! Can you make more videos on data structures covering all topics plz
You are phenomenal... Loved your video.💕💕
Very nice little lecture, but I cannot figure it out which would be an example of a good real developer scenario in which a tree would be the more efficient way.
Great explanation, thanks.
Sincerely,
Someone who smokes a lot of trees
"lets add a constructor to make our lives easier" god this developer life
if only the constructor initialised the left and right to null
itsajin why? Node is a reference type....it’ll be implicitly null....
There must be an implementation of delete function in this video, it will add more value to it.
You're awesome Ms. McDowell! Many thanks.
Well explained. Exactly what I needed. Thank you.
Are use the same technique to schedule my priorities and tasks throughout the day.
omg trees are this simple? fantastic explanation that too in this much short time.
Great explanation. My only question is how to implement it such that the node can contain an arbitrary (but homogeneous) data type?
Just what I needed right now.
I love this explanation, but I’m kind of surprised that you had all of the BST methods in the Node class. It works, I guess, but just seems like an inappropriate place to put them.
2 Questions: method printInOrder() what is System.out.printIn(data) doing? Also in this in-order example.. why after 5 is the next “in-order” number 8? Shouldn’t it be 10?
I understand recursively we’re traversing to the Left most depth node in the binary tree ( up until left == null ) - but I’m confused how we’re printing from that point forward.
Similar question here. Once it's on the bottom of the left side of the tree, on either left or right node, how does it jump back up to root node?
Well explained. Works like charm !! Thanks
Fantastic breakdown. You are the truth.
Gayle you is amezing!! I love you , ty for being inspiration for all women in cs area.
I think this is cleaner... but is it better/worse? (Its C++, if any wonder)
bool contains(int value){
if(this == nullptr)
return false;
else if(value == data)
return true;
else if(valuecontains(value);
else if(value>data)
return right->contains(value);
return false;
}
Hi, very well explained and I request to you can you make more complete data structure videos on C, C++ and Java.
Honestly, after watching this video I got confused. I am sure that this code works fine, but why is there no Binary Tree structure being created? All the functions which ideally should be written for a BST data structure are written for a node. So if I wanted to construct a BST, do I create a Node object??
This explanation makes my life simple against Binary Tree Thanks Alot !! :)
In the insert method, what if the tree is empty, how it would insert the first node, since the code says left or right
Thank you for posting such a useful article!
I actually understood binary trees after this video! Wow.
Its a very nice and simple way to do all that stuff , but what about the destructor? How would you do it ?
Very nicely explained! Well done!
Very clear explanation, and nice drawings!
Awesone. Thanks from Brazil. Excelent explanation!
10 OUT OF 10.
IF I UNDERSTOOD, EVERYONE CAN.
Great explanation. Thanks very much.
the perfect video on trees
You are an amazing educator! Thank you
that was more useful than my entire semester
Thank you, Gayle. Well explained.