| | AVL tree - Wikipedia, the free encyclopedia |
 | | In an AVL tree the heights of the two child subtrees of any node differ by at most one, therefore it is also called height-balanced. |
 | | While AVL trees are theoretically quite sound, they are not commonly implemented due to their high implementation complexity to keep it balanced, making development less effective when compared to self-correcting tree structures, such as splay trees or heaps. |
 | | Insertion into an AVL tree may be carried out by inserting the given value into the tree as if it were an unbalanced binary search tree, and then retracing one's steps toward the root, rotating about any nodes which have become unbalanced during the insertion (see tree rotation). |
| en.wikipedia.org /wiki/AVL_tree (652 words) |