Preorder vs Inorder vs Postorder

In Preorder Traversal, the root node is visited first, followed by the left and right subtrees. Inorder Traversal starts with the left subtree, visits the root, and then the right subtree, often used in binary search trees. Postorder Traversal begins with the left subtree, moves to the right subtree, and visits the root last, useful for deleting nodes. In this article, we will discuss the Tree Traversal Techniques used in data structure and algorithms with their differences.

Preorder traversal is defined as a type of tree traversal that follows the Root-Left-Right policy where:

• The root node of the subtree is visited first.
• Then the left subtree is traversed.
• At last, the right subtree is traversed.

Inorder traversal is defined as a type of tree traversal technique that follows the Left-Root-Right pattern, such that:

• The left subtree is traversed first.
• Then the root node for that subtree is traversed.
• Finally, the right subtree is traversed.

Postorder traversal is defined as a type of tree traversal that follows the Left-Right-Root policy such that for each node:

• The left subtree is traversed first.
• Then the right subtree is traversed.
• Finally, the root node of the subtree is traversed.

Below is the Implementation of the above idea:

Pre-order traversal: 1 2 4 5 3 6 
In-order traversal: 4 2 5 1 3 6 
Post-order traversal: 4 5 2 6 3 1