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countLeftNodes

Language/Type: Java binary trees

Write a method named countLeftNodes that accepts returns the number of left children in a binary tree. Your method accepts as its parameter a TreeNode that refers to the root of the tree. A left child is a node that appears as the root of the left-hand subtree of another node. For example, the following tree has four left children (the nodes storing the values 5, 1, 4, and 7): 

(3 (5 (1)) (2 (4 (7)) (6)))

Assume that you are interacting with TreeNodes as defined below: 

public class TreeNode {
    public int data;
    public TreeNode left;
    public TreeNode right;
    
    public TreeNode() { ... }
    public TreeNode(int data) { ... }
    public TreeNode(int data, TreeNode left, TreeNode right) { ... }
}
Method: Write a Java method as described, not a complete program or class.

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