Java/DataStructures/Graphs/FloydWarshall.java at master · java66liu/Java · GitHub

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package DataStructures.Graphs;

import java.util.Arrays;

import java.util.Scanner;

public class FloydWarshall {

private int DistanceMatrix[][];

private int numberofvertices;//number of vertices in the graph

public static final int INFINITY = 999;

public FloydWarshall(int numberofvertices) {

DistanceMatrix = new int[numberofvertices + 1][numberofvertices + 1];//stores the value of distance from all the possible path form the source vertex to destination vertex

Arrays.fill(DistanceMatrix, 0);

this.numberofvertices = numberofvertices;

}

public void floydwarshall(int AdjacencyMatrix[][])//calculates all the distances from source to destination vertex

{

for (int source = 1; source <= numberofvertices; source++) {

for (int destination = 1; destination <= numberofvertices; destination++) {

DistanceMatrix[source][destination] = AdjacencyMatrix[source][destination];

}

for (int intermediate = 1; intermediate <= numberofvertices; intermediate++) {

for (int source = 1; source <= numberofvertices; source++) {

for (int destination = 1; destination <= numberofvertices; destination++) {

if (DistanceMatrix[source][intermediate] + DistanceMatrix[intermediate][destination]

< DistanceMatrix[source][destination])

// if the new distance calculated is less then the earlier shortest

// calculated distance it get replaced as new shortest distance

{

DistanceMatrix[source][destination] = DistanceMatrix[source][intermediate]

+ DistanceMatrix[intermediate][destination];

}

for (int source = 1; source <= numberofvertices; source++)

System.out.print("\t" + source);

System.out.println();

for (int source = 1; source <= numberofvertices; source++) {

System.out.print(source + "\t");

for (int destination = 1; destination <= numberofvertices; destination++) {

System.out.print(DistanceMatrix[source][destination] + "\t");

}

System.out.println();

}

public static void main(String... arg) {

Scanner scan = new Scanner(System.in);

System.out.println("Enter the number of vertices");

int numberOfVertices = scan.nextInt();

int[][] adjacencyMatrix = new int[numberOfVertices + 1][numberOfVertices + 1];

System.out.println("Enter the Weighted Matrix for the graph");

for (int source = 1; source <= numberOfVertices; source++) {

for (int destination = 1; destination <= numberOfVertices; destination++) {

adjacencyMatrix[source][destination] = scan.nextInt();

if (source == destination) {

adjacencyMatrix[source][destination] = 0;

continue;

}

if (adjacencyMatrix[source][destination] == 0) {

adjacencyMatrix[source][destination] = INFINITY;

}

System.out.println("The Transitive Closure of the Graph");

FloydWarshall floydwarshall = new FloydWarshall(numberOfVertices);

floydwarshall.floydwarshall(adjacencyMatrix);

scan.close();

}

Java/DataStructures/Graphs/FloydWarshall.java at master · java66liu/Java · GitHub

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