Reverse level order traversal of binary tree in java

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This is part of java binary tree tutorial.
In this post, we will see about Reverse Level Order binary tree traversal in java. In previous post, we have already seen Level order traversal. In reverse level order traversal, we will visit last level first, then second last and eventually first level.

Reverse Level Order traversal:

Reverse Level order traversal of below binary tree will be:

We will use stack  for Reverse Level Order traversal.

Steps for Reverse Level order traversal algorithm:

1. Create empty queue and push root node to it.
2. Do the following when queue is not empty
   • Pop a node from queue and print it
   • Push right child of popped node to queue if not null
   • Push left child of popped node to queue if not null
   • Push popped node to stack
3. Pop node from stack and print it

So Reverse Level Order traversal will work as below:

Lets create java program :

Run above program and you will get following output:

Java Binary tree tutorial

• Binary tree in java
• Binary tree preorder traversal
• Binary tree postorder traversal
• Binary tree inorder traversal
• Binary tree level order traversal
• Binary tree spiral order traversal
• Binary tree reverse level order traversal
• Binary tree boundary traversal
• Print leaf nodes of binary tree
• Count leaf nodes in binary tree
• get maximum element in binary tree
• Print all paths from root to leaf in binary tree
• Print vertical sum of binary tree in java
• Get level of node in binary tree in java
• Lowest common ancestor(LCA) in binary tree in java

Please go through java interview programs for more such programs.