The establishment of binary tree and various traversal example codes in Java

This is a common interview question. For example, through the preorder and middle order traversal of binary tree, we can get the sequence traversal of binary tree

First order + middle order - > create tree

Suppose there is a binary tree, as follows:

The traversal order is:

Now give preorder and inorder to build a binary tree, or give inorder and postorder to build a binary tree. In fact, it is the same

Tree node definition:

Achievements:

Middle order + post order is actually the same. It's not written here

Various Traversals

Postorder traversal

Draw inferences from one instance. The first order is the same as the middle order. It is not written here

level traversal

You can use a queue. Initially, add the root node to the queue. When the queue is not empty, take the node of the queue head and print the node value of the node. If the left and right children of the node are not empty, add the left and right children to the queue

Depth first and breadth first

In fact, it's just another way of saying that depth first is sequence traversal, and breadth first is sequence traversal

Main function:

summary

The above is all about the establishment of binary tree and various traversal example codes in Java. I hope it will be helpful to you. Interested friends can continue to refer to this website:

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