Authors:
Stuart Reges, Marty Stepp
Chapter:
Binary Trees
Exercise:
Exercises
Question:5 | ISBN:9780136091813 | Edition: 2
Question
Write a method called countEvenBranches that returns the number of branch nodes in a binary tree that contain even numbers. A branch node has one or two children (i.e., it is not a leaf). For example, if a variable t refers to reference tree #2, then the call t.countEvenBranches() should return 3 because there are three branch nodes with even values ( 2 , 8 , and 6 ). Notice that leaf nodes with even values are not included (the nodes storing 0 and 4 ).
Add the following method to the IntTree class from this chapter. You may define additional private methods to implement your public method if necessary. Several problem descriptions refer to the following reference binary trees:
Answer
Implementation of countEvenBranches method:
public int countEvenBranches()
{
return countEvenBranches(overallRoot);
}
private int countEvenBranches(IntTreeNode root)
{
if(root == null)
{
return 0;
}
else if(root.data % 2 == 0 && root.left != null
&& root.right != null)
{
return 1 + countEvenBranches(root.left)
+ countEvenBranches(root.right);
}
else
{
return countEvenBranches(root.left)
+ countEvenBranches(root.right);
}
}