Solution: Number of Nodes in a Given Graph Level

class CountNodes {
    public static int numberOfNodesInGivenLevel(Graph g, int source, int level) {
        int count = 0;
        int num_of_vertices = g.getVertices();
        // Integer array to hold the history of visited nodes (by default - false)
        // Make a node visited whenever you add it into the queue
        int visited[] = new int[num_of_vertices];
        // Create a linkedlist array called Queue
        LinkedList<Integer> queue = new LinkedList<Integer>();
        // Mark the visited nodes as true by setting value to 1 and add them to the queue
        visited[source] = 1;
        queue.add(source);
        // Traverse while the queue is not empty
        while (queue.size() != 0) {
            // Poll the vertex/node from queue
            source = queue.poll();
            // Get adjacent vertices to the current node from the list
            LinkedList<Integer> Llist[];
            Llist = g.getAdj();
            Iterator<Integer> i = Llist[source].listIterator();
            while (i.hasNext()) {
                int temp = i.next();
                // If not already visited, add to the queue
                if (visited[temp] == 0) {
                    visited[temp] = visited[source] + 1;
                    if (visited[temp] < level) {
                        queue.add(temp);
                    }
                }
            }
        }
        // Calculate the count for the level
        for (int i = 0; i < num_of_vertices; i++) {
            if (visited[i] == level) {
                count++;
            }
        }
        return count;
    }
}
class Main {
    public static void main(String args[]) {
        Graph g = new Graph(6);
        g.addEdge(0, 1);
        g.addEdge(0, 2);
        g.addEdge(1, 3);
        g.addEdge(2, 3);
        g.addEdge(3, 5);
        g.addEdge(2, 4);
        int answer;
        answer = CountNodes.numberOfNodesInGivenLevel(g, 0, 1);
        System.out.println(answer);
        answer = CountNodes.numberOfNodesInGivenLevel(g, 0, 2);
        System.out.println(answer);
        answer = CountNodes.numberOfNodesInGivenLevel(g, 0, 3);
        System.out.println(answer);
        answer = CountNodes.numberOfNodesInGivenLevel(g, 0, 4);
        System.out.println(answer);
    }
}