c# System.OutOfMemoryException How can I solve it?

Question

Hi I am using this function to calculate all the possible combinations of A List of Object "Ricerca" when I try to calculte the combination of more than 24 elemnts I get the System.OutOfMemory Exception. Is there a way I can solve this problem?

this is the function I use:

 private static List<List<Ricerca>> GetAllCombos(List<Ricerca> list)
    {
        int comboCount = (int)Math.Pow(2, list.Count) - 1;
        List<List<Ricerca>> result = new List<List<Ricerca>>();
        for (int i = 1; i < comboCount + 1; i++)
        {
            // make each combo here
            result.Add(new List<Ricerca>());
            for (int j = 0; j < list.Count; j++)
            {
                if ((i >> j) % 2 != 0)
                    result.Last().Add(list[j]);
            }
        }
        return result;
    }

Thanks for your help

Answer 1

Do you really need to hold them all in memory at once or would it be sufficient to get each combination one at a time so you can do something with it?

    private static IEnumerable<List<Ricerca>> GetAllCombos(IReadOnlyCollection<Ricerca> list)
    {
        var comboCount = (int)Math.Pow(2, list.Count) - 1;
        for (var i = 1; i < comboCount + 1; i++)
        {
            // make each combo here
            yield return list.Where((t, j) => (i >> j) % 2 != 0).ToList();
        }
    }