fork download
copy 
  1. import java.util.Comparator;
  2. import java.util.InputMismatchException;
  3. import java.util.PriorityQueue;
  4. import java.util.Scanner;
  5.  
  6.   class BestFirstSearch
  7. {
  8.     private PriorityQueue<Vertex> priorityQueue;
  9.     private int heuristicvalues[];
  10.     private int numberOfNodes;
  11.  
  12.     public static final int MAX_VALUE = 999;
  13.  
  14.     public BestFirstSearch(int numberOfNodes)
  15.     {
  16.         this.numberOfNodes = numberOfNodes;
  17.         this.priorityQueue = new PriorityQueue<Vertex>(this.numberOfNodes,
  18.         new Vertex());
  19.     }
  20.  
  21.     public void bestFirstSearch(int adjacencyMatrix[][], int[] heuristicvalues,int source)
  22.     {
  23.         int evaluationNode;
  24.         int destinationNode;
  25.         int visited[] = new int [numberOfNodes + 1];
  26.         this.heuristicvalues = heuristicvalues;
  27.  
  28.         priorityQueue.add(new Vertex(source, this.heuristicvalues[source]));
  29.         visited[source] = 1;
  30.  
  31.         while (!priorityQueue.isEmpty())
  32.         {
  33.             evaluationNode = getNodeWithMinimumHeuristicValue();
  34.             destinationNode = 1;
  35.  
  36.             System.out.print(evaluationNode + "\t");			
  37.             while (destinationNode <= numberOfNodes)
  38.             {
  39.                 Vertex vertex = new Vertex(destinationNode,this.heuristicvalues[destinationNode]);
  40.                 if ((adjacencyMatrix[evaluationNode][destinationNode] != MAX_VALUE 			                                           
  41.                       && evaluationNode != destinationNode)&& visited[destinationNode] == 0)
  42.                 {
  43.                     priorityQueue.add(vertex);
  44.                     visited[destinationNode] = 1;
  45.                 }
  46.                 destinationNode++;
  47.             }
  48.         }
  49.     }
  50.  
  51.     private int getNodeWithMinimumHeuristicValue()
  52.     {
  53.         Vertex vertex = priorityQueue.remove();
  54.         return vertex.node;
  55.     }
  56.  
  57.     public static void main(String[] arg)
  58.     {
  59.         int adjacency_matrix[][];
  60.         int number_of_vertices;
  61.         int source = 0;
  62.         int heuristicvalues[];
  63.  
  64.         Scanner scan = new Scanner(System.in);
  65.         try
  66.         {
  67.             System.out.println("Enter the number of vertices");
  68.             number_of_vertices = scan.nextInt();
  69.             adjacency_matrix = new int[number_of_vertices + 1][number_of_vertices + 1];
  70.             heuristicvalues = new int[number_of_vertices + 1];
  71.  
  72.             System.out.println("Enter the Weighted Matrix for the graph");
  73.             for (int i = 1; i <= number_of_vertices; i++)
  74.             {
  75.                 for (int j = 1; j <= number_of_vertices; j++)
  76.                 {
  77.                     adjacency_matrix[i][j] = scan.nextInt();
  78.                     if (i == j)
  79.                     {
  80.                         adjacency_matrix[i][j] = 0;
  81.                         continue;
  82.                     }
  83.                     if (adjacency_matrix[i][j] == 0)
  84.                     {
  85.                         adjacency_matrix[i][j] = MAX_VALUE;
  86.                     }
  87.                 }
  88.             }
  89.             for (int i = 1; i <= number_of_vertices; i++)
  90.             {
  91.                 for (int j = 1; j <= number_of_vertices; j++)
  92.                 {
  93.                     if (adjacency_matrix[i][j] == 1 && adjacency_matrix[j][i] == 0)
  94.                     {
  95.                         adjacency_matrix[j][i] = 1;
  96.                     }
  97.                 }
  98.             }
  99.  
  100.             System.out.println("Enter the heuristic values of the nodes");
  101.             for (int vertex = 1; vertex <= number_of_vertices; vertex++)
  102.             {
  103.                 System.out.print(vertex + ".");
  104.                 heuristicvalues[vertex] = scan.nextInt();
  105.                 System.out.println();
  106.             }
  107.  
  108.             System.out.println("Enter the source ");
  109.             source = scan.nextInt();
  110.  
  111.             System.out.println("The graph is explored as follows");
  112.             BestFirstSearch bestFirstSearch = new BestFirstSearch(number_of_vertices);
  113.             bestFirstSearch.bestFirstSearch(adjacency_matrix, heuristicvalues,source);
  114.  
  115.        } catch (InputMismatchException inputMismatch)
  116.        {
  117.            System.out.println("Wrong Input Format");
  118.        }
  119.        scan.close();
  120.    }
  121. }
  122.  
  123. class Vertex implements Comparator<Vertex>
  124. {
  125.     public int heuristicvalue;
  126.     public int node;
  127.  
  128.     public Vertex(int node, int heuristicvalue)
  129.     {
  130.         this.heuristicvalue = heuristicvalue;
  131.         this.node = node;
  132.     }
  133.  
  134.     public Vertex()
  135.     {
  136.  
  137.     } 
  138.  
  139.     @Override 
  140.     public int compare(Vertex vertex1, Vertex vertex2)
  141.     {
  142.         if (vertex1.heuristicvalue < vertex2.heuristicvalue)
  143.             return -1;
  144.         if (vertex1.heuristicvalue > vertex2.heuristicvalue)
  145.             return 1;
  146.         return 0;
  147.     }
  148.  
  149.     @Override
  150.     public boolean equals(Object obj)
  151.     {
  152.         if (obj instanceof Vertex)
  153.         {
  154.             Vertex node = (Vertex) obj;
  155.             if (this.node == node.node)
  156.             {
  157.                 return true;
  158.             }
  159.         }
  160.         return false;
  161.     }
  162. }
  163.  
Success #stdin #stdout 0.15s 321280KB
comments (?)
stdin
copy 
4
0 5 8 4
0 0 6 0
5 0 0 7
0 0 0 2
4
5 
3 
2
1
stdout
copy 
Enter the number of vertices
Enter the Weighted Matrix for the graph
Enter the heuristic values of the nodes
1.
2.
3.
4.
Enter the source 
The graph is explored as follows
1	4	3	2
https://ideone.com/qn7Lqm
language:
Java (HotSpot 12)
created:
8 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!