public void Add(Node neighbour, int w)
        {
            weightedEdge edge = new weightedEdge(neighbour);

            edge.weight = w;
            neighbourList.Add(edge);
        }
        public void AddBack(Node neighbour, string oneWayTag)
        {
            weightedEdge edge = new weightedEdge(oneWayTag);

            edge.neighbour = neighbour;

            backList.Add(edge);
        }
        public void AddNeighbour(Node neighbour, string oneWayTag)
        {
            weightedEdge edge = new weightedEdge(oneWayTag);

            edge.neighbour = neighbour;
            if (oneWayTag != "backward")
            {
                countOfForward++;
            }
            neighbourList.Add(edge);
        }
        public void AddSym(Node neighbour)
        {
            weightedEdge edge = new weightedEdge(neighbour);

            symList.Add(edge);
        }