class Vertex {
    	public int label;
    	public boolean visited;
    	public Vertex(int label){
    		this.label = label;
    		this.visited = false;
    	}
    }
    class Graph{
    	private int adjMaxtrix[][];
    	private Vertex vertexList[];
    	private Stack<Integer> stack;
    	private Queue<Integer> queue;
    	
    	public Graph(){
    		adjMatrix = new int[20][20];
    		stack = new Stack();
    		queue = new Queue();
    	}
    	
    	// 시간복잡도 O(V^2), 인접리스트로 하면 O(V+E)
    	public void dfs() {
    		vertexList[0].visited = true;
    		displayVertex(0);
    		stack.push(0);
    		while(!stack.isEmpty()){
    			int v = getAdjUnvisitedVertex(stack.peek());
    			if(v == -1){
    				stack.pop();
    			} else {
    				vertexList[v].visited = true;
    				displayVertex(v);
    				stack.push(v);
    			}
    		}
    	}
    
    	public dfsR(int n){
    		vertexList[n].visited = true;
    		displayVertex(n);
    		for(int i = 0; i < vertexList.length; i++){
    			if(adjMatrix[v][i] == 1 && vertexList[i].visited == false){
    				dfsR(i);
    			}
    		}
    	}
    
    	// 시간복잡도 O(V^2), 인접리스트는 O(V+E)
    	public bfs(){
    		vertexList[0].visited = true;
    		displayVertex(0);
    		queue.enqueue(0);
    		int v2;
    		while(!queue.isEmpty())[
    			int v1 = queue.dequeue();
    			while((v2 = getAdjUnvisitedVertex(v1)) != -1){
    				vertexList[v2].visited = true;
    				displayVertex(v2);
    				queue.enqueue(v2);
    			}
    		}
    	}
    	
    	public int getAdjUnvisitedVertex(int v){
    		for(int i = 0; i < vertexList.length; i++){
    			if(adjMatrix[v][i] == 1 && vertexList[i].visited == false){
    				return i;
    			}
    		}
    		return -1;
    	}
    }