# What Is Binary Tree Sort in Data Structure?

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Larry Thompson

Binary Tree Sort is a popular sorting algorithm in the field of data structures. It is based on the concept of a binary tree, which is a hierarchical data structure where each node has at most two children nodes. In this article, we will explore the working principle of Binary Tree Sort and how it can be used to efficiently sort a collection of elements.

## Understanding Binary Trees

Before diving into Binary Tree Sort, let’s quickly recap the basics of binary trees. A binary tree consists of nodes that are connected to form a tree-like structure. Each node can have at most two children nodes, often referred to as the left child and the right child.

Binary Tree Properties:

• A binary tree can be empty, meaning it doesn’t contain any nodes.
• If a binary tree is not empty, it consists of a root node and zero or more additional nodes.
• Each node in a binary tree can have at most two children nodes.

## The Working Principle of Binary Tree Sort

Binary Tree Sort follows a simple yet efficient approach to sort elements:

1. Create an empty binary search tree (BST).
2. Iteratively insert each element from the collection into the BST.
3. In-order traverse the BST to retrieve the elements in sorted order.

Note: In Binary Search Trees, all elements in the left subtree are smaller than or equal to the root value, while all elements in the right subtree are greater than or equal to the root value. This property helps us achieve sorting through an in-order traversal.

### Step-by-Step Explanation

Let’s understand the working principle of Binary Tree Sort with an example:

Step 1: Create an empty BST.

Step 2: Insert each element from the collection into the BST.

Step 3: In-order traverse the BST to retrieve the elements in sorted order.

Consider an unsorted collection: [9, 5, 2, 7, 12]

#### Step 1: Create an empty BST

We start by creating an empty binary search tree (BST).

#### Step 2: Insert each element into the BST

We iteratively insert each element from the collection into the BST. The resulting BST would look like this:

```        9
/ \
5   12
/ \
2   7
```

#### Step 3: Retrieve elements in sorted order

We perform an in-order traversal of the BST to retrieve all elements in sorted order. In this case, it would be [2, 5, 7, 9, 12].

## The Complexity Analysis of Binary Tree Sort

The time complexity of Binary Tree Sort is determined by two main operations:

• Insertion:
• The average-case time complexity for insertion in a binary tree is O(log n), where n is the number of elements.
• In the worst-case scenario (when the tree is highly unbalanced), insertion can take O(n) time.
• In-order Traversal:
• In-order traversal of a binary tree has a time complexity of O(n), where n is the number of elements.

The overall time complexity of Binary Tree Sort is O(n log n) in the average case and O(n^2) in the worst case. The space complexity is O(n) since it requires additional space to store the binary tree.

## Conclusion

Binary Tree Sort is an efficient sorting algorithm based on the concept of binary trees. It involves creating a binary search tree, inserting elements into it, and then performing an in-order traversal to retrieve the sorted elements.

While Binary Tree Sort has a time complexity of O(n log n) in the average case, it can potentially degrade to O(n^2) if the tree becomes highly unbalanced. Nonetheless, it remains a useful sorting algorithm in certain scenarios.

Now that you have a solid understanding of Binary Tree Sort, you can experiment with this algorithm and explore its applications in various programming languages.