Depth-First Traversal of Binary Trees

Introduction

Tree traversal is a common operation in computer science and is used to visit each node in a tree exactly once. Depth-first search (DFS) is a popular algorithm for traversing trees and graphs. In this challenge, we will implement DFS on a binary tree.

Skills Graph

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Tree Dfs

Problem

Implement depth-first traversals (in-order, pre-order, post-order) on a binary tree. For in-order traversal, we visit the left subtree, then the current node, and then the right subtree. For pre-order traversal, we visit the current node, then the left subtree, and then the right subtree. For post-order traversal, we visit the left subtree, then the right subtree, and then the current node.

Requirements

To complete this challenge, we need to meet the following requirements:

We can assume we already have a Node class with an insert method.

When we process each node, we should call an input method visit_func on the node.

We can assume this fits in memory.

Example Usage

Here are some examples of how to use the DFS algorithm:

In-Order Traversal

For a binary tree with values 5, 2, 8, 1, and 3, the in-order traversal would be 1, 2, 3, 5, and 8. For a binary tree with values 1, 2, 3, 4, and 5, the in-order traversal would be 1, 2, 3, 4, and 5.

Pre-Order Traversal

For a binary tree with values 5, 2, 8, 1, and 3, the pre-order traversal would be 5, 2, 1, 3, and 8. For a binary tree with values 1, 2, 3, 4, and 5, the pre-order traversal would be 1, 2, 3, 4, and 5.

Post-Order Traversal

For a binary tree with values 5, 2, 8, 1, and 3, the post-order traversal would be 1, 3, 2, 8, and 5. For a binary tree with values 1, 2, 3, 4, and 5, the post-order traversal would be 5, 4, 3, 2, and 1.