Question

In the following graph, write a Java program using Topological Sort.

b.

please write java code and show me the output.

Thank you :)

Answer 1

CODE:  
import java.io.*;
import java.util.*;
  

public class Graph
{
private int V; // No. of vertices
private LinkedList<Integer> adj[]; // Adjacency List
  
//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); }
  
// A recursive function used by topologicalSort
void topologicalSortUtil(int v, boolean visited[],
Stack stack)
{
// Mark the current node as visited.
visited[v] = true;
Integer i;
  
  
Iterator<Integer> it = adj[v].iterator();
while (it.hasNext())
{
i = it.next();
if (!visited[i])
topologicalSortUtil(i, visited, stack);
}
  
// Push current vertex to stack which stores result
stack.push(new Integer(v));
}
  

void topologicalSort()
{
Stack stack = new Stack();
  
// Mark all the vertices as not visited
boolean visited[] = new boolean[V];
for (int i = 0; i < V; i++)
visited[i] = false;
  
// Call the recursive helper function to store
// Topological Sort starting from all vertices
// one by one
for (int i = 0; i < V; i++)
if (visited[i] == false)
topologicalSortUtil(i, visited, stack);
  
// Print contents of stack
while (stack.empty()==false)
System.out.print(stack.pop() + " ");
}
  
// Driver method
public static void main(String args[])
{
// Create a graph given in the above diagram
Graph g = new Graph(8);
g.addEdge(0, 1);
g.addEdge(0, 3);
g.addEdge(1, 2);
g.addEdge(3, 4);
g.addEdge(3, 5);
g.addEdge(4, 5);
g.addEdge(4, 6);
g.addEdge(5, 6);
g.addEdge(5, 7);
  
System.out.println("Following is a Topological " +
"sort of the given graph");
g.topologicalSort();
}
}

OUTPUT:

Following is a Topological sort of the given graph
0 3 4 5 7 6 1 2 

NOTE: Consider

a as 0,

b as 1,

c as 2,

d as 3,

e as 4,

f as 5,

g as 6,

h as 7