Final answer:
The minimum size of an AVL tree for which an insertion could trigger a double rotation is 4.
Step-by-step explanation:
The minimum size of an AVL tree for which an insertion could trigger a double rotation is 4.
In an AVL tree, a double rotation is triggered when a node is inserted causing an imbalance in the tree. This imbalance occurs when the heights of the left and right subtrees of a node differ by a factor of more than 1.
For example, if the original AVL tree has the values [1, 2, 3], an insertion of 4 would cause a double rotation because inserting 4 would result in an imbalance where the left subtree has a height of 2 and the right subtree has a height of 0, violating the balance property of the AVL tree