Complete binary tree inserter - mock interview interviewee's code

CompleteBinaryTreeInserter.cs

using System;

// To execute C#, please define "static void Main" on a class
// named Solution.

class Solution
{
    static void Main(string[] args)
    {
        for (var i = 0; i < 5; i++)
        {
            Console.WriteLine("Hello, World");
        }
    }
}

A complete binary tree is a binary tree in which every level, except possibly the last, is completely filled, and all nodes 
are as far left as possible.

Write a data structure CBTInserter that is initialized with a complete binary tree and supports the following operations:

CBTInserter(TreeNode root) initializes the data structure on a given tree with head node root;
CBTInserter.insert(int v) will insert a TreeNode into the tree with value node.val = v so that the tree remains complete, and
returns the value of the parent of the inserted TreeNode;
CBTInserter.get_root() will return the head node of the tree.
 

Example 1:

Input: inputs = ["CBTInserter","insert","get_root"], inputs = [[[1]],[2],[]]
Output: [null,1,[1,2]]
Example 2:

Input: inputs = ["CBTInserter","insert","insert","get_root"], inputs = [[[1,2,3,4,5,6]],[7],[8],[]]
Output: [null,3,4,[1,2,3,4,5,6,7,8]]
 

Note:

The initial given tree is complete and contains between 1 and 1000 nodes.
CBTInserter.insert is called at most 10000 times per test case.
Every value of a given or inserted node is between 0 and 5000.    
    
 /**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     public int val;
 *     public TreeNode left;
 *     public TreeNode right;
 *     public TreeNode(int x) { val = x; }
 * }
 */
    
    // q root => left 1, right1 , left1.left, right1
public class CBTInserter {
    TreeNode rootNode;
    Queue<TreeNode> q = new Queue<TreeNode>();
    Queue<TreeNode> lq = new Queue<TreeNode>();
    public CBTInserter(TreeNode root) {
        this.rootNode = root;
        q.Enqueue(root);
        
        while(q.Count()!=0)
        {
            TreeNode node = q.Dequeue();
            if(node.left == null) || 
                (node.right == null)
                lq.Enqueue(node);
            if(node.left != null)
                q.Enqueue(node.left);
            if(node.right != null)
                q.Enqueue(node.right);
        }        
    }
    
    public int Insert(int v) {
        // curr = first find the left most leaf node
        TreeNode temp = lq.Peek(); 
        lq.Enqueue(new TreeNode(v));
        
        if(temp.left==null)
           temp.left = lq.Last();
        else
        {
           temp.right = lq.Last();
            
        }
        
        return temp.val;
        
        // create a node and deque the leaf node and add the new node as the new leaf node
        // curr . 
        
    }
    
    public TreeNode Get_root() {
        return root;
    }
}

/**
 * Your CBTInserter object will be instantiated and called as such:
 * CBTInserter obj = new CBTInserter(root);
 * int param_1 = obj.Insert(v);
 * TreeNode param_2 = obj.Get_root();
 */