79 lines
3.7 KiB
Java
79 lines
3.7 KiB
Java
import java.util.Scanner;
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public class FloydWarshall
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{
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private int DistanceMatrix[][];
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private int numberofvertices;//number of vertices in the graph
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public static final int INFINITY = 999;
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public FloydWarshall(int numberofvertices)
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{
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DistanceMatrix = new int[numberofvertices + 1][numberofvertices + 1];//stores the value of distance from all the possible path form the source vertex to destination vertex
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Arrays.fill(DistanceMatrix, 0);
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this.numberofvertices = numberofvertices;
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}
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public void floydwarshall(int AdjacencyMatrix[][])//calculates all the distances from source to destination vertex
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{
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for (int source = 1; source <= numberofvertices; source++)
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{
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for (int destination = 1; destination <= numberofvertices; destination++)
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{
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DistanceMatrix[source][destination] = AdjacencyMatrix[source][destination];
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}
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}
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for (int intermediate = 1; intermediate <= numberofvertices; intermediate++)
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{
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for (int source = 1; source <= numberofvertices; source++)
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{
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for (int destination = 1; destination <= numberofvertices; destination++)
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{
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if (DistanceMatrix[source][intermediate] + DistanceMatrix[intermediate][destination]
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< DistanceMatrix[source][destination])//if the new distance calculated is less then the earlier shortest calculated distance it get replaced as new shortest distance
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DistanceMatrix[source][destination] = DistanceMatrix[source][intermediate]
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+ DistanceMatrix[intermediate][destination];
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}
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}
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}
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for (int source = 1; source <= numberofvertices; source++)
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System.out.print("\t" + source);
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System.out.println();
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for (int source = 1; source <= numberofvertices; source++)
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{
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System.out.print(source + "\t");
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for (int destination = 1; destination <= numberofvertices; destination++)
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{
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System.out.print(DistanceMatrix[source][destination] + "\t");
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}
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System.out.println();
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}
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}
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public static void main(String... arg)
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{
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int Adjacency_Matrix[][];
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int numberofvertices;
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Scanner scan = new Scanner(System.in);
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System.out.println("Enter the number of vertices");
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numberofvertices = scan.nextInt();
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Adjacency_Matrix = new int[numberofvertices + 1][numberofvertices + 1];
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System.out.println("Enter the Weighted Matrix for the graph");
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for (int source = 1; source <= numberofvertices; source++)
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{
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for (int destination = 1; destination <= numberofvertices; destination++)
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{
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Adjacency_Matrix[source][destination] = scan.nextInt();
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if (source == destination)
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{
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Adjacency_Matrix[source][destination] = 0;
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continue;
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}
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if (Adjacency_Matrix[source][destination] == 0)
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{
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Adjacency_Matrix[source][destination] = INFINITY;
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}
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}
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}
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System.out.println("The Transitive Closure of the Graph");
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FloydWarshall floydwarshall = new FloydWarshall(numberofvertices);
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floydwarshall.floydwarshall(adjacency_matrix);
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scan.close();
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}
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}
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