public State Search(string startNodeName, string endNodeName)
        {
            Node startNode = Program.instance.graph[startNodeName];
            Node endNode = Program.instance.graph[endNodeName];

            List<State> stanjaZaObradu = new List<State>();

            stanjaZaObradu.Add(new State(startNode));

            while (stanjaZaObradu.Count > 0)
            {
                stanjaZaObradu.OrderBy(stanje => stanje.Cost);
                State naObradi = stanjaZaObradu[0];
                stanjaZaObradu.Remove(naObradi);

                if (naObradi.Node.Name == endNode.Name)
                {
                    return naObradi;
                }
                else
                {
                    List<State> mogucaSledecaStanja = naObradi.children();
                    stanjaZaObradu.AddRange(mogucaSledecaStanja);
                }
            }

            return null;
        }