Accenture challenge using algorithm implementation from here: http://algs4.cs.princeton.edu/code/

Main.java

import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.List;

public class Main {
    private static int getNode(int i, int j) {
        return i * 1000 + j;
    }

    public static void main(String[] args) {
        EdgeWeightedDigraph test = new EdgeWeightedDigraph(1000 * 1000);
        int first = 0;

        try {
            List<String> lines = Files.readAllLines(Paths.get("ShortestPathProblem.txt"), Charset.defaultCharset());
            for (int i = 0; i < lines.size(); i++) {
                String line = lines.get(i);
                String elms[] = line.split(";");

                if (i == 0) {
                    first = Integer.parseInt(elms[0]);
                }

                for (int j = 0; j < elms.length; j++) {
                    int weight = Integer.parseInt(elms[j]);
                    if (i != 0) {
                        test.addEdge(new DirectedEdge(getNode(i - 1, j), getNode(i, j), weight));
                    }
                    if (i != 999) {
                        test.addEdge(new DirectedEdge(getNode(i + 1, j), getNode(i, j), weight));
                    }
                    if (j != 0) {
                        test.addEdge(new DirectedEdge(getNode(i, j - 1), getNode(i, j), weight));
                    }
                    if (j != 999) {
                        test.addEdge(new DirectedEdge(getNode(i, j + 1), getNode(i, j), weight));
                    }
                }
            }
            System.out.println("done adding edges");

        } catch (IOException e) {
            e.printStackTrace();
        }

        DijkstraSP path = new DijkstraSP(test, 0);
        System.out.println(path.distTo(1000 * 1000 - 1) + first);
    }
}