DFS and BFS

package vikram.HR;

// Java program to print DFS traversal from a given given graph

import java.util.*;
import java.util.LinkedList;

// This class represents a directed graph using adjacency list
// representation
public class DFSBFS {
    private int V;   // No. of vertices

    // Array  of lists for Adjacency List Representation
    private java.util.LinkedList<Integer> adj[];

    // Constructor
    public DFSBFS(int v) {
        V = v;
        adj = new java.util.LinkedList[v];
        for (int i = 0; i < v; ++i)
            adj[i] = new java.util.LinkedList();
    }

    //Function to add an edge into the graph
    void addEdge(int v, int w) {

        adj[v].add(w);  // Add w to v's list.
    }

    // A function used by DFS
    void DFSUtil(int v, boolean visited[]) {
        // Mark the current node as visited and print it
        visited[v] = true;
        System.out.print(v + " ");

        // Recur for all the vertices adjacent to this vertex
        Iterator<Integer> i = adj[v].listIterator();
        while (i.hasNext()) {
            int n = i.next();
            if (!visited[n])
                DFSUtil(n, visited);
        }
    }

    // The function to do DFS traversal. It uses recursive DFSUtil()
    void DFS(int v) {
        // Mark all the vertices as not visited(set as
        // false by default in java)
        boolean visited[] = new boolean[V];

        // Call the recursive helper function to print DFS traversal
        DFSUtil(v, visited);
    }

    // prints BFS traversal from a given source s
    void BFS(int s) {
        // Mark all the vertices as not visited(By default
        // set as false)
        boolean visited[] = new boolean[V];

        // Create a queue for BFS
       java.util.LinkedList<Integer> queue = new LinkedList<Integer>();

        // Mark the current node as visited and enqueue it
        visited[s] = true;
        queue.add(s);

        while (queue.size() != 0) {
            // Dequeue a vertex from queue and print it
            s = queue.poll();
            System.out.print(s + " ");
            // Get all adjacent vertices of the dequeued vertex s
            // If a adjacent has not been visited, then mark it
            // visited and enqueue it
            Iterator<Integer> i = adj[s].listIterator();
            while (i.hasNext()) {
                int n = i.next();
                if (!visited[n]) {
                    visited[n] = true;
                    queue.add(n);
                }
            }
        }
    }

    public static void main(String args[]) {
        DFSBFS g = new DFSBFS(4);

        g.addEdge(0, 1);
        g.addEdge(0, 2);
        g.addEdge(1, 2);
        g.addEdge(2, 0);
        g.addEdge(2, 3);
        g.addEdge(3, 3);

        System.out.println("Following is Depth First Traversal " +
                "(starting from vertex 2)");
        System.out.println("BFS:-");
        g.BFS(2);
        System.out.println("\nDFS:-");
        g.DFS(2);
    }
}
// This code is contributed by Aakash Hasija