Floyd-Warshallův algoritmus, nefunguje proč? – Java – Fórum – Programujte.com

Zdravím,

proč mi nefunguje tento kód? Kód jsem na šel na internetu, chci vidět jak funguje, sám bych ho nevymyslel. Při spuštění to napíše "Enter the number of vertices", tak napíšu '4' a potvrdím tlačítkem 'enter', ale víc to už neudělá? Kde je chyba? Najde se někdo kdo poradí? Moc děkuji za jakoukoliv odpověď. S pozdravem Martin. 

import java.util.Scanner;
 
public class FloydWarshall
{
    private int distancematrix[][];
    private int numberofvertices;
    public static final int INFINITY = 999;
 
    public FloydWarshall(int numberofvertices)
    {
        distancematrix = new int[numberofvertices + 1][numberofvertices + 1];
        this.numberofvertices = numberofvertices;
    }
 
    public void floydwarshall(int adjacencymatrix[][])
    {
        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])
                        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)
    {
        int adjacency_matrix[][];
        int numberofvertices;
 
        Scanner scan = new Scanner(System.in);
        System.out.println("Enter the number of vertices");
        numberofvertices = scan.nextInt();
 
        adjacency_matrix = 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++)
            {
                adjacency_matrix[source][destination] = scan.nextInt();
                if (source == destination)
                {
                    adjacency_matrix[source][destination] = 0;
                    continue;
                }
                if (adjacency_matrix[source][destination] == 0)
                {
                    adjacency_matrix[source][destination] = INFINITY;
                }
            }
        }
 
        System.out.println("The Transitive Closure of the Graph");
        FloydWarshall floydwarshall = new FloydWarshall(numberofvertices);
        floydwarshall.floydwarshall(adjacency_matrix);
        scan.close();
    }
}

Mě ten zdroj funguje.

- zadám velikost matice

- pak zadám jednotlivé prvky matice

- pak přijde jejich výstup

1) index 0 0 se nevypíše

2) prvky na diagonále jsou nulové

3) ale co to přesně s tou maticí dělá to netuším.

Funguje jak má.