We have seen in the previous section that if nodes are inserted into a tree in a sequential order, it becomes slow and behaves more or less like a list; that is, each node has exactly one child node. To improve the performance of the tree data structure, we generally like to reduce the height of the tree as much as possible to balance the tree by filling up each row in the tree. This process is called balancing the tree.

There are different types of self-balancing trees, such as red-black trees, AA trees, and scapegoat trees. These balance the tree during each operation that modifies the tree, such as insert or delete. There are also external algorithms that balance a tree. The benefits of these are that you don't need to balance the tree on every single operation and can leave balancing to the point where you need it.