protected override IEnumerable <ScoreboardSortModel> GetEnumerable()
        {
            cats2 = Categories.ToDictionary(t => t.CategoryId);

            var rt = RankCache
                     .Where(a => cats2.ContainsKey(a.Team.CategoryId))
                     .GroupBy(a => cats2[a.Team.CategoryId].SortOrder)
                     .OrderBy(g => g.Key);

            foreach (var g in rt)
            {
                var prob = new ScoreboardProblemStatisticsModel[Problems.Length];
                for (int i = 0; i < Problems.Length; i++)
                {
                    prob[i] = new ScoreboardProblemStatisticsModel();
                }
                yield return(new ScoreboardSortModel(GetViewModel(IsPublic, g, prob), prob));
            }
        }