All language subtitles for 15 - Preorder Binary Tree Traversal English

So far we've talked about traversing a binary tree adding to a tree deleting from a tree but there's

a few other things that it's important to know especially if you're taking an algorithm class or you're

needing to create a good visualization for search and that's what binary trees are great for and the

very first thing we're going to do in this tutorial is go over what's called a pre order traversal.

And there is a few properties associated with it.

And I'm going to walk through the way the process works on the sample binary tree right here.

So the very first thing that you're going to do in a preorder traversal is visit the root.

So right here you can see that the root is 7.

And so we're going to traverse a tree and actually put this into an array appear at the top.

So for the array we're going to start off in or just say the first value we get is 7 because we're traversing

a tree and pre order the next step is actually to move to the left.

So we would move to this one value right here and we'd put this one in the array.

From there we would go further down to the left and get zero.

Put that in the array and then we're just going to keep on going down the list so now we're going to

come back up because zero doesn't have any children.

It's leafnode.

So then we're going to go over to three.

And so three is going to be the next value.

And from there we have to

and then back up to 3 and back down to 5 and evens is pretty straightforward it's more a process of

understanding just how it works.

But still finish this one out so you can see it.

So from five go down to four and then go back up to 5 and then go to six.

And so we've completed the left side of the binary search tree.

So now that we've done that we traverse all the way back up.

And then we go to that next value which is going to be 9.

So we'll go 7 to 9.

So this is on the right subtree and then from 9 would go down to 8 and then to 10 and that's it.

So this is how you traverse a tree using the pre order method when you're traversing a binary search

tree.

In the next video we're going to go over what's called the Post order traversal.

So see you in that video.