IntSetComparer comp = new IntSetComparer();
bool add1 = comp.AddUniqueSet("1,2,3");     // unique
bool add2 = comp.AddUniqueSet("1,3,2");     // duplicate
Console.WriteLine("Add1 = {0}\nAdd2 = {1}", add1, add2);

// ... (code from a) ...
(new List<string>{
    "56,69,26,0",   // unique
    "3,2,1",        // 2. duplicate
    "2,156",        // unique
    "156,2",        // duplicate
    "32"            // unique
}).ForEach(s => comp.AddUniqueSet(s));
int nonDuplicates = comp.GetUniquesCount();
int duplicates = comp.GetDuplicatesCount();            
Console.WriteLine("Non-duplicates = {0}\nDuplicates = {1}", nonDuplicates, duplicates);

// ... (code from a,b) ...
Console.WriteLine("Most frequent duplicate group: {0}", comp.GetMostFrequentSet());

// ... (code from a,b,c) ...
(new List<string>{
    "56,,0",  
    null,              
    "156,ab"
}).ForEach(s => comp.AddUniqueSet(s));
comp.GetInvalidInputsReport(Console.Out);

using System.Collections.Generic;
using System.Linq;

namespace SetComparer.Sets
{
    public class StringSet : SetBase<string>
    {
        public StringSet(List<string> set) : base(set) { }
        public StringSet(string set) : base(set) { }
        public StringSet() { }

        public override List<string> Parse(string set)
        {
            if (set == null)
            {
                ThrowAndLogFormatException(set);
            }
            return set.Split(',').ToList();
        }
    }
}

using SetComparer.Sets;

namespace SetComparer.Comparers
{
    public class StringSetComparer : SetComparer<StringSet, string> { }
}