What is the main purpose of a balanced binary search tree?

• A. To guarantee O(log n) insert/search/delete performance.
• B. To minimize memory usage.
• C. To always store integers in sorted order only.
• D. To allow negative values only.

Answer: (A)

Balancing keeps the tree height roughly proportional to log2(n), so the core operations—insert, search, and delete—perform in O(log n) time. This guarantees fast, predictable performance because you traverse a path from the root to a target node whose length is about the height of the tree. If the tree becomes unbalanced, it can degenerate into a tall structure that makes these operations behave like O(n), which defeats the purpose. The other ideas don’t capture this focus: balancing doesn’t aim to minimize memory usage, and while a BST stores keys in sorted order, it isn’t limited to integers or to negative values.