# What Is Tree and Its Types in Data Structure?

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Larry Thompson

A tree is a popular data structure in computer science that represents a hierarchical structure. It consists of nodes connected by edges, where each node can have zero or more child nodes.

The topmost node in a tree is called the root, and every other node is a descendant of the root. Trees are widely used to represent hierarchical relationships between different entities such as files and folders in an operating system, organization structures, family trees, etc.

## Types of Trees

### 1. Binary Tree

A binary tree is a type of tree where each node can have at most two children, known as the left child and the right child. These children are ordered, meaning that there is a specific left-to-right order among them.

To visualize a binary tree:

• Each node can have up to two children.
• The left child comes before the right child.

### 2. Binary Search Tree (BST)

A binary search tree is a type of binary tree with an additional property: for any given node, all elements in its left subtree are smaller than the node’s value, while all elements in its right subtree are larger.

This property allows for efficient searching within the tree. When searching for an element in a BST, we compare the Target value with the current node’s value and move to either the left or right subtree accordingly.

### 3. AVL Tree

An AVL (Adelson-Velskii and Landis) tree is another type of binary search tree that maintains balance by enforcing a height difference constraint between its left and right subtrees. This constraint ensures that the depth of any two leaf nodes differs by at most one level.

The balancing property of AVL trees helps maintain efficient search, insertion, and deletion operations, ensuring the tree remains balanced.

### 4. B-Tree

A B-tree is a self-balancing tree data structure designed to efficiently maintain large amounts of data. It is commonly used in file systems and databases.

B-trees are characterized by:

• Multiple keys and pointers in each node.
• Ability to have more than two children per node.
• Guaranteed balance, allowing for efficient search, insertions, and deletions even with large datasets.

### 5. Trie

A trie (pronounced “try”) is a tree-like data structure used to store a dynamic set or associative array where the keys are usually strings. The word “trie” comes from the word retrieval.

Tries have the following properties:

• Each node represents a common prefix of its descendants’ keys.
• The root node represents an empty string or null key.
• The path from the root to any node spells out a valid key from the trie’s set of keys.

## Conclusion

Trees are versatile data structures that find applications in various domains of computer science. Understanding different types of trees and their properties is essential for designing efficient algorithms and solving complex problems effectively.

By using trees appropriately, you can organize and navigate through hierarchical relationships efficiently, making it easier to store, search, and manipulate structured data in your programs.