Solution Review: Implement Breadth First Search

using System;
using System.Collections.Generic;
namespace chapter_5
{
    class Challenge_1
    {
        static void bfsTraversal_helper(Graph g, int source, bool[] visited, ref string result)
        {
            if (g.getVertices() < 1)
            {
                return;
            }
            //Create Queue(Implemented in previous chapters) for Breadth First Traversal and enqueue source in it
            //myQueue queue(g.getVertices());
            Queue<int> queue = new Queue<int> { };
            queue.Enqueue(source);
            visited[source] = true;
            int current_node;
            //Traverse while queue is not empty
            while (queue.Count != 0)
            {
                //Dequeue a vertex/node from queue and add it to result
                current_node = queue.Dequeue();
                result += current_node.ToString();
                //Get adjacent vertices to the current_node from the array,
                //and if they are not already visited then enqueue them in the Queue
                LinkedList.Node temp = (g.getArray())[current_node].GetHead();
                while (temp != null)
                {
                    if (!visited[temp.data])
                    {
                        queue.Enqueue(temp.data);
                        visited[temp.data] = true; //Visit the current Node
                    }
                    temp = temp.nextElement;
                }
            } //end of while
        }
        static string bfsTraversal(Graph g)
        {
            string result = "";
            //Bool Array to hold the history of visited nodes
            //Make a node visited whenever you push it into stack
            bool[] visited = new bool[g.getVertices()];
            for (int i = 0; i < g.getVertices(); i++)
            {
                visited[i] = false;
            }
            for (int i = 0; i < g.getVertices(); i++)
            {
                if (!visited[i])
                    bfsTraversal_helper(g, i, visited, ref result);
            }
            visited = null;
            return result;
        }
        static void Main(string[] args)
        {
            Graph g = new Graph(6);
            g.addEdge(1, 2);
            g.addEdge(1, 3);
            g.addEdge(2, 4);
            g.addEdge(2, 5);
            Console.WriteLine(bfsTraversal(g));
        }
    }
}