Solution: Calculate the Number of Nodes in a Graph Level

class Program
{
    /// <summary>
    /// Calculates the number of nodes at a given level in the graph.
    /// </summary>
    /// <param name="graph">The graph.</param>
    /// <returns>The total number of nodes at the given level.</returns>
    public static int NumberOfNodes(Graph myGraph, int level)
    {
        int source = 0;
        // Mark all the vertices as not visited
        // All element are instantiated to 0 by default
        int[] visited = new int[myGraph.graph.Length];
        // Create a queue 
        Queue<int> queue = new Queue<int>();
        // Mark the source node as
        // visited and enqueue it
        queue.Enqueue(source);
        visited[source] = 1;
        while (queue.Count != 0)
        {
            // Dequeue a vertex from queue
            source = queue.Dequeue();
            // Get all adjacent vertices of the
            // dequeued vertex source. If a adjacent
            // has not been visited, then mark it
            // visited and enqueue it
            while (myGraph.graph[source] != null)
            {
                int data = myGraph.graph[source].Vertex;
                if (visited[data] == 0)
                {
                    queue.Enqueue(data);
                    visited[data] = visited[source] + 1;
                }
                myGraph.graph[source] = myGraph.graph[source].Next;
            }
        }
        // Counting number of nodes at given level
        int result = 0;
        for (int i = 0; i < myGraph.graph.Length; i++)
        {
            if (visited[i] == level)
            {
                result += 1;
            }
        }
        return result;
    }
    // Main to test above function
    static void Main(string[] args)
    {
        int V = 5;
        Graph g = new Graph(V);
        g.AddEdge(0, 1);
        g.AddEdge(0, 2);
        g.AddEdge(1, 3);
        g.AddEdge(1, 4);
        Console.WriteLine(NumberOfNodes(g, 2));
    }
}