Gfrktyl

I got this code from tutorial horizon and I'm trying to modify it to get it to:

1. only output the shortest path from source to destination, currently outputs shortest path to all edges from source




2. output the pathway to the shortest path

static class Edge {

    int start;

    int end;

    int weight;

    int length;

    Edge previous;



    public Edge(int start, int end, int weight) {

        this.start = start;

        this.end = end;

        this.weight = weight;

        //this.length = length;

    }

}

static class ResultSet{

    int parent;

    int weight;

}



static class Graph {

    int vertex;

    LinkedList<Edge> adjacencylist;



    Graph(int vertex) {

        this.vertex = vertex;

        adjacencylist = new LinkedList[vertex];

        for (int i = 0; i < vertex; i++) {

            adjacencylist[i] = new LinkedList<>();

        }

    }





    public void addEdge(int start, int end, int weight) {

        Edge edge = new Edge(start, end, weight);

        adjacencylist[start].addFirst(edge);



        edge = new Edge(end,start,weight);

        adjacencylist[end].addFirst(edge);

    }



    public ArrayList<String> dijkstra(int startvertex){

        boolean SPT = new boolean[vertex];

        int distance = new int[vertex];

        for(int i =0; i<vertex;i++){

            distance[i] = Integer.MAX_VALUE;

        }

        PriorityQueue<Pair<Integer,Integer>> pq = new PriorityQueue<>(vertex, new Comparator<Pair<Integer, Integer>>() {

            @Override

            public int compare(Pair<Integer, Integer> o1, Pair<Integer, Integer> o2) {

                int key1 = o1.getKey();

                int key2 = o2.getKey();

                return key1 - key2;

            }

        });

        distance[0] = 0;

        Pair<Integer,Integer> p0 = new Pair<>(distance[0],0);

        pq.offer(p0);

        while(!pq.isEmpty()){

            Pair<Integer,Integer> extractedPair = pq.poll();

            int extractedVertex = extractedPair.getValue();

            if(SPT[extractedVertex]==false){

                SPT[extractedVertex] = true;

                LinkedList<Edge> list = adjacencylist[extractedVertex];

                for (int i = 0; i<list.size();i++){

                    Edge edge = list.get(i);

                    //System.out.println(edge.start + ":" + edge.weight + ":" + edge.end);

                    int end  = edge.end;

                    if(SPT[end] == false){

                        int newKey = distance[extractedVertex] + edge.weight;

                        int currentKey = distance[end];

                        if(currentKey>newKey){

                            Pair<Integer,Integer> p = new Pair<>(newKey,end);

                            pq.offer(p);

                            distance[end] = newKey;

                        }

                    }

                }

            }

        }

        printDijkstra(distance,startvertex);

        ArrayList<String> stuff = checkDijkstra(distance,startvertex);

        return stuff;

    }