Binary Tree Level Order traversal in java

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This is 5th part of java binary tree tutorial.

In this post, we will see about Level Order binary tree traversal in java.

Level Order traversal

Level order traversal of below binary tree will be:

We will use Queue for Level Order traversal.This algorithm is very similar to Breadth first search of graph.
Steps for Level order traversal algorithm:

1. Create empty `queue` and pust `root` node to it.
2. Do the following when `queue` is not empty
• `Pop` a node from `queue` and print it
• `Push left child` of popped node to `queue` if not null
• `Push right child` of popped node to `queue` if not null
Example:
Lets say your binary tree is :

So Level Order traversal will work as below:

Lets create java program for level order traversal:

Run above program and you will get following output:

Level Order traversal of binary tree will be:
40 20 60 10 30 50 70

Java Binary tree tutorial

Please go through java interview programs for more such programs.

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