74 lines
3.4 KiB
Java
74 lines
3.4 KiB
Java
package DataStructures.Graphs;
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import java.util.Arrays;
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import java.util.Scanner;
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public class FloydWarshall {
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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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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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for (int destination = 1; destination <= numberofvertices; destination++) {
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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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for (int source = 1; source <= numberofvertices; source++) {
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for (int destination = 1; destination <= numberofvertices; destination++) {
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if (DistanceMatrix[source][intermediate] + DistanceMatrix[intermediate][destination]
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< DistanceMatrix[source][destination])
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// if the new distance calculated is less then the earlier shortest
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// calculated distance it get replaced as new shortest distance
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{
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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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}
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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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System.out.print(source + "\t");
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for (int destination = 1; destination <= numberofvertices; destination++) {
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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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Scanner scan = new Scanner(System.in);
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System.out.println("Enter the number of vertices");
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int numberOfVertices = scan.nextInt();
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int[][] adjacencyMatrix = 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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for (int destination = 1; destination <= numberOfVertices; destination++) {
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adjacencyMatrix[source][destination] = scan.nextInt();
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if (source == destination) {
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adjacencyMatrix[source][destination] = 0;
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continue;
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}
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if (adjacencyMatrix[source][destination] == 0) {
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adjacencyMatrix[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(adjacencyMatrix);
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scan.close();
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}
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}
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