Given the BinaryTree class (partially shown below), select an expression to complete the static recursive helper method countLeaves, which returns the number of leaf nodes in the binary tree rooted at node n.
A)n.right == null
B)n.left == null || n.right == null
C)n.left == null
D)n.left == null && n.right == null

Question

Given the BinaryTree class (partially shown below), select an expression to complete the static recursive helper method countLeaves, which returns the number of leaf nodes in the binary tree rooted at node n.  
A)n.right == null 
B)n.left == null || n.right == null 
C)n.left == null 
D)n.left == null && n.right == null

Quizplus · Accepted Answer

A leaf node is defined as a node that has no left or right child. Therefore, the expression that checks if n has no left and right child (Option D) is the correct choice to count the number of leaf nodes.

Given the BinaryTree Class (Partially Shown Below), Select an Expression