payal-kothari
8/28/2017 - 8:43 PM

## Graph DFS.java

``````// Java program to print DFS traversal from a given given graph
import java.io.*;
import java.util.*;

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

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

// 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); // 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);
}

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 Depth First Traversal "+
"(starting from vertex 2)");

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