Graph Traversals

GraphNode.java

public class GraphNode{
	int vertex;
	ArrayList<Integer> edges = new ArrayList<Integer>();

	public GraphNode(int vertex,ArrayList<Integer> edges){
		this.vertex = vertex;
		this.edges = edges;
	}
	public ArrayList<Integer> getEdges(){return edges;}
	public String toString(){
		StringBuffer str = new StringBuffer();
		for(int i=0;i<edges.size();i++)
			str.append(edges.get(i)+" ");
		str.append("\n");
		return str.toString();
		
	}

	public static void BFS(int vertex,ArrayList<GraphNode> graph){
		System.out.println("Breadth first Traversal:");
		LinkedList<Integer> vertexQueue = new LinkedList<Integer>();
		boolean[] visited = new boolean[graph.size()];
		visited[vertex]= true;
		System.out.println(vertex);
		vertexQueue.addLast(vertex);
		while(vertexQueue.size()>0){
			int v = vertexQueue.removeFirst();
			ArrayList<Integer> listOfVertices = graph.get(v).getEdges();
			for(int e:listOfVertices){
				if(!visited[e])
				{
					System.out.println(e);
					visited[e]=true;
					vertexQueue.addLast(e);
				}
			}
		}
	}
	
	public static void DFS(int vertex,ArrayList<GraphNode> graph){
		System.out.println("Depth First Traversal:");
		Stack<Integer> stack = new Stack<Integer>();
		boolean[] visited = new boolean[graph.size()];
		visited[vertex]=true;
		stack.push(vertex);
		ArrayList<Integer> edges =null;
		int v;
		while(stack.size()!=0){
			v= stack.pop();
			System.out.println(v);
			edges = graph.get(v).getEdges();
			for(int tmp:edges){
				if(!visited[tmp])
				{
					visited[tmp]=true;
					stack.push(tmp);
				}
			}
		}
	}
		
	public static void main(String[] args){
		/*Scanner scanner = new Scanner(System.in);
		System.out.println("Constructing a graph:");
		System.out.println("Enter the number of vertices:");
		int vertices = scanner.nextInt();
		GraphNode g = null;
		ArrayList<GraphNode> graph = new ArrayList<GraphNode>();
		for(int vertex=0; vertex<vertices;vertex++){
			ArrayList listOfVertices= new ArrayList<Integer>();
			System.out.println("Enter the edges for "+vertex+" and press enter -1 to esape:");
			String input = scanner.next();
			while(!input.equals("-1")){
				listOfVertices.add(Integer.parseInt(input));
				input = scanner.next();
			}
			
			g= new GraphNode( vertex, listOfVertices);
			graph.add(g);
		}

		for(int i=0; i<graph.size(); i++){
			System.out.print(i+"->"+graph.get(i));
		}*/
		ArrayList<GraphNode> graph=new ArrayList<GraphNode>();
		ArrayList<Integer> edges = new ArrayList<Integer>();
		edges.add(1);
		edges.add(2);
		graph.add(0,new GraphNode(0, edges));
		edges = new ArrayList<Integer>();
		edges.add(0);
		edges.add(2);
		edges.add(3);
		graph.add(1,new GraphNode(1, edges));
		edges = new ArrayList<Integer>();
		edges.add(0);
		edges.add(1);
		edges.add(4);
		graph.add(2,new GraphNode(2, edges));
		edges = new ArrayList<Integer>();
		edges.add(1);
		edges.add(5);
		graph.add(3,new GraphNode(3, edges));
		edges = new ArrayList<Integer>();
		edges.add(2);
		edges.add(5);
		graph.add(4,new GraphNode(4, edges));
		edges = new ArrayList<Integer>();
		edges.add(3);
		edges.add(4);
		edges.add(6);
		graph.add(5,new GraphNode(5, edges));
		edges = new ArrayList<Integer>();
		edges.add(5);
		graph.add(6,new GraphNode(6, edges));
		for(int i=0; i<graph.size(); i++){
			System.out.print(i+"->"+graph.get(i));
		}
		GraphNode.BFS(0, graph);
		GraphNode.DFS(0, graph);
	}

}