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IterativeDepthFirstTraversalOfGraph.java
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IterativeDepthFirstTraversalOfGraph.java
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import java.util.*;
public class Main
{
// This class represents a directed graph using adjacency
// list representation
static class Graph
{
int V; //Number of Vertices
LinkedList<Integer>[] adj; // adjacency lists
//Constructor
Graph(int V)
{
this.V = V;
adj = new LinkedList[V];
for (int i = 0; i < adj.length; i++)
adj[i] = new LinkedList<Integer>();
}
//To add an edge to graph
void addEdge(int v, int w)
{
adj[v].add(w); // Add w to v’s list.
}
// prints all not yet visited vertices reachable from s
void DFS(int s)
{
// Initially mark all vertices as not visited
Vector<Boolean> visited = new Vector<Boolean>(V);
for (int i = 0; i < V; i++)
visited.add(false);
// Create a stack for DFS
Stack<Integer> stack = new Stack<>();
// Push the current source node
stack.push(s);
while(stack.empty() == false)
{
// Pop a vertex from stack and print it
s = stack.peek();
stack.pop();
// Stack may contain same vertex twice. So
// we need to print the popped item only
// if it is not visited.
if(visited.get(s) == false)
{
System.out.print(s + " ");
visited.set(s, true);
}
// Get all adjacent vertices of the popped vertex s
// If a adjacent has not been visited, then puah it
// to the stack.
Iterator<Integer> itr = adj[s].iterator();
while (itr.hasNext())
{
int v = itr.next();
if(!visited.get(v))
stack.push(v);
}
}
}
}
public static void main(String[] args)
{
// Total 5 vertices in graph
Graph g = new Graph(5);
g.addEdge(1, 0);
g.addEdge(0, 2);
g.addEdge(2, 1);
g.addEdge(0, 3);
g.addEdge(1, 4);
System.out.println("Following is the Depth First Traversal");
g.DFS(0);
}
}