JAVA

Java BFS

// Java Breath First Search
// ------------------------

import java.util.*;                

public class BreathFirstSearch {

    int V;
    ArrayList<Integer> adj[];

    BreathFirstSearch(int noofvertex) {
        V = noofvertex;
        adj = new ArrayList[noofvertex];
        for (int i = 0; i < noofvertex; i++) {
            adj[i] = new ArrayList<>();
        }
    }

    void edge(int x, int y) {
        adj[x].add(y);
    }

    void bfs(int sourcevertex) {
        boolean[] visited = new boolean[V];
        ArrayList<Integer> a1 = new ArrayList<Integer>();
        visited[sourcevertex] = true;
        a1.add(sourcevertex);
        while (!a1.isEmpty()) {
            sourcevertex = a1.remove(0);
            System.out.print(sourcevertex + "");
            Iterator i = adj[sourcevertex].iterator();
            while (i.hasNext()) {
                int n = (int)  i.next();
                if (!visited[n]) {
                    visited[n] = true;
                    a1.add(n);
                }
            }
        }

    }

    public static void main(String[] args) {
        BreathFirstSearch g1 = new BreathFirstSearch(6);
        g1.edge(0, 1);
        g1.edge(0, 2);
        g1.edge(0, 5);
        g1.edge(1, 0);
        g1.edge(1, 2);
        g1.edge(2, 0);
        g1.edge(2, 1);
        g1.edge(2, 3);
        g1.edge(2, 4);
        g1.edge(3, 2);
        g1.edge(4, 2);
        g1.edge(4, 5);
        g1.edge(5, 0);

        g1.bfs(0);
    }
}

bfs java

// Java program to print BFS traversal from a given source vertex.
// BFS(int s) traverses vertices reachable from s.
import java.io.*;
import java.util.*;

// This class represents a directed graph using adjacency list
// representation
class Graph
{
    private int V;   // No. of vertices
    private LinkedList<Integer> adj[]; //Adjacency Lists

    // Constructor
    Graph(int v)
    {
        V = v;
        adj = new LinkedList[v];
        for (int i=0; i<v; ++i)
            adj[i] = new LinkedList();
    }

    // Function to add an edge into the graph
    void addEdge(int v,int w)
    {
        adj[v].add(w);
    }

    // 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
        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);
                }
            }
        }
    }

    // Driver method to
    public static void main(String args[])
    {
        Graph g = new Graph(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 Breadth First Traversal "+
                           "(starting from vertex 2)");

        g.BFS(2);
    }
}
// This code is contributed by Aakash Hasija