Write a method called countLeftNodes that returns the number of left children in the tree. A left child is a node that appears as the root of the left-hand subtree of another node. For example,...

Write a method called countLeftNodes that returns the number of left children in the tree. A left child is a node that appears as the root of the left-hand subtree of another node. For example, reference tree #1 has 3 left children (the nodes storing the values 5 , 1 , and 4 ).