public List<string> FindClusters()
{
    var nodesToUnite = new List<string>();
    var currentNodes = Nodes();
    var nodesNumber = currentNodes.Count;

    for (var i = 0; i < nodesNumber; i ++)
    {
        var firstVertexSet = relationShip(currentNodes[i]);
        for (var j = i + 1; j < nodesNumber; j ++)
        {
            if (new HashSet<string>(firstVertexSet).SetEquals(relationShip(currentNodes[j])))
            {
                nodesToUnite.Add(currentNodes[i]);
            }
        }
    }
    return nodesToUnite;
}