AVL Tree An AVL tree is a type of self-balancing binary search tree, named after its inventors Adelson-Velsky and Landis. It is a data structure used for storing and retrieving ordered data efficiently. In an AVL tree, the height of the left and right subtrees of any node differ by at most 1, ensuring that the tree remains balanced and ensuring fast search, insertion, and deletion operations. When an AVL tree is modified (e.g., by inserting or deleting a node), the balance of the tree may be disturbed. To restore balance, rotations can be performed on the subtrees to ensure that the height difference between the left and right subtrees of every node is no more than 1. AVL trees are widely used in various applications, such as in databases, computer networks, and computer graphics, where fast searching, insertion, and deletion operations are crucial. They offer a trade-off between time and space efficiency, and can be used as an alternative to other self-balancing trees such as red-black trees or splay trees.