# What Are the Use of AVL Trees in Data Structure?

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Heather Bennett

An AVL tree is a self-balancing binary search tree that maintains height balance during operations. It is named after its inventors, Adelson-Velsky and Landis. AVL trees are a fundamental data structure in computer science and are widely used in various applications.

## Why use AVL Trees?

AVL trees provide efficient operations for searching, insertion, and deletion. The main advantage of using AVL trees over regular binary search trees is that they guarantee the height balance property, which ensures that the tree remains balanced even after multiple insertions or deletions.

When working with large datasets or performing frequent dynamic updates on the tree, maintaining balance becomes crucial to ensure optimal performance. An unbalanced binary search tree can degenerate into a linked list, resulting in poor time complexity for search operations.

## How do AVL Trees Work?

An AVL tree is a binary search tree with an additional balance factor stored at each node. The balance factor is calculated as the difference between the heights of the left and right subtrees. If this difference exceeds 1 (i.e., the tree becomes unbalanced), appropriate rotations are performed to restore balance.

• Left-Left Case: When the left subtree of the left child grows taller, a right rotation is performed on the unbalanced node.
• Right-Right Case: When the right subtree of the right child grows taller, a left rotation is performed on the unbalanced node.
• Left-Right Case: When the right subtree of the left child grows taller, first a left rotation is performed on its left child followed by a right rotation on the unbalanced node.
• Right-Left Case: When the left subtree of the right child grows taller, first a right rotation is performed on its right child followed by a left rotation on the unbalanced node.

The rotations maintain the height balance property of AVL trees and ensure efficient operations.

## Benefits of AVL Trees

The use of AVL trees offers several benefits:

• Efficient Searching: AVL trees provide fast search operations with a time complexity of O(log n) since they are always balanced.
• Efficient Insertion and Deletion: The self-balancing property ensures that insertions and deletions can be done in O(log n) time, providing efficient dynamic updates to the tree.
• Guaranteed Worst-case Performance: Unlike regular binary search trees, AVL trees guarantee a worst-case time complexity of O(log n) for all operations, regardless of the input order.

## Limitations of AVL Trees

While AVL trees offer many advantages, they also have some limitations:

• Overhead: Maintaining balance requires additional memory to store balance factors at each node, increasing memory usage compared to regular binary search trees.
• Slightly Slower Operations: Due to the need for balancing rotations, AVL tree operations may be slightly slower than those of regular binary search trees. However, the difference is negligible for most practical scenarios.

### In Conclusion

AVL trees are an essential data structure that provides efficient searching, insertion, and deletion operations while maintaining height balance. They ensure optimal performance even with large datasets or frequent dynamic updates. Although they have some overhead and slightly slower operations compared to regular binary search trees, their benefits outweigh these limitations in most cases.