2-3一种特殊的树,它满足两个条件:(1)每个内部结点有两个或三个子结点;(2)所有的到根的路径长度相同;如果一棵2-39个,那么它可能有_________个非。 (多项)2-3 tree is a special kind of tree, it satisfy:(1)Every internal node has 2 or 3 child nodes.(2)All the leaf nodes have the same length of the path to the root node. If a 2-3 tree has 9 leaf nodes, then it may have __________ non-leaf nodes.(There are more than one correct answers)