Data Structures and Algorithms
with Object-Oriented Design Patterns in Java 
Program 
defines the constructor and getM methods
of the MWayTree class.
The constructor takes a single, integer-valued argument
that specifies the desired value of M.
Provided M is greater than or equal to two,
the constructor creates two arrays of length M.
Note, a node in an M-way tree contains at most M-1 keys.
In the implementation shown, key[0] is never used.
Because the constructor allocates arrays of length M,
its worst-case running time is O(M).
The getM method shown in Program
returns the value of M.
That is, it returns the maximum number of subtrees that a node is
allows to have.
This is simply given by the length of the subtree array.
The running time of the getM method is clearly O(1).
Copyright © 1998 by Bruno R. Preiss, P.Eng. All rights reserved.