如何在没有源的情况下拓扑排序邻接矩阵？

Question

所以，我试图找出一种方法来实现这个代码，我可以拓扑排序我的邻接矩阵，而无需输入源代码。我试着查一查，但在大多数情况下，其他方法离我很远。有什么帮助吗？

代码：

import java.util.Stack;
import java.util.Scanner;
import java.util.InputMismatchException;


public class Top
{
    private Stack<Integer> stack;

    public Top()
    {
        stack = new Stack<Integer>();
    }

    public int [] topological(int adjacency_matrix[][], int source) throws NullPointerException
    {
        int number_of_nodes = adjacency_matrix[source].length - 1;
        int[] topological_sort = new int [number_of_nodes + 1];
        int pos = 1;
        int j ;
        int visited[] = new int[number_of_nodes + 1];
        int element = source;
        int i = source;
        visited[source] = 1;
        stack.push(source);

        while (!stack.isEmpty())
        {
            element = stack.peek();
            while (i <= number_of_nodes)
            {
                if (adjacency_matrix[element][i] == 1 && visited[i] == 1)
                {
                    if (stack.contains(i))
                    {
                        System.out.println("TOPOLOGICAL SORT NOT POSSIBLE");
                        return null;
                    }
                }
                if (adjacency_matrix[element][i] == 1 && visited[i] == 0)
                {
                    stack.push(i);
                    visited[i] = 1;
                    element = i;
                    i = 1;
                    continue;
                }
                i++;
            }
            j = stack.pop();
            topological_sort[pos++] = j;
            i = ++j;
        }
        return topological_sort;
    }

    public static void main(String...arg)
    {
        int number_no_nodes, source;
        Scanner scanner = null;
        int topological_sort[]  = null;
        try
    {
        System.out.println("Enter the number of nodes in the graph");
        scanner = new Scanner(System.in);
        number_no_nodes = scanner.nextInt();

        int adjacency_matrix[][] = new int[number_no_nodes + 1][number_no_nodes + 1];
        System.out.println("Enter the adjacency matrix");
        for (int i = 0; i < number_no_nodes; i++)
        {
            for (int j = 0; j < number_no_nodes; j++)
            {
                System.out.print("Please enter the value for array["+i+"]["+j+"] (between -10 and 10):");
                int val = scanner.nextInt();
                if(val>5 || val< -5)
                {
                    System.out.println("Invalid value.");
                    continue;
                }
                adjacency_matrix[i][j] = val;
            }
        }

        System.out.println("Enter the source for the graph");
        source = scanner.nextInt();

        System.out.println("The Topological sort for the graph is given by ");
        Top toposort = new Top();
        topological_sort = toposort.topological(adjacency_matrix, source);
        System.out.println();
        for (int i = topological_sort.length - 1; i > 0; i-- )
        {
            if (topological_sort[i] != 0)
            System.out.print(topological_sort[i]+"\t");
        }
    }
    catch(InputMismatchException inputMismatch)
    {
        System.out.println("Incorrect Input format");
    }
    catch(NullPointerException nullPointer)
    {

    }
    scanner.close();
    }
}