using System;

using System;

using System.Collections.Generic;

using System.Linq;

using Newtonsoft.Json;

​

public class Program

{

    public static void Main()

    {

        var list = new List<string>{"example.string.1", "example.string.2", "example.anotherstring.1", "example.anotherstring.2", "System", "System.Diagnostics", "System.Text", "System.Collections.Generic", "System.Linq", "System.Diagnostics.1", "System.Text.1", "System.Collections.Generic.1", "System.Linq.1", "System.Diagnostics.2", "System.Text.2", "System.Collections.Generic.2", "System.Linq.2"};

        var groups = list.Select(x => x.Split('.')).GroupBy(x => x.FirstOrDefault()).Select(x => new RawValue(x.Key, x.Select(y => y.Skip(1))));

        var settings = new JsonSerializerSettings{NullValueHandling = NullValueHandling.Ignore};

        var result = GroupNameSpaces(groups);

        var json = JsonConvert.SerializeObject(result, Formatting.Indented, settings);

        Console.WriteLine(json);

    }

​

    private static IEnumerable<RawValue> GetRawValues(RawValue value)

    {

        return value.Values.Where(x => x.Any()).GroupBy(x => x.FirstOrDefault()).Select(x => new RawValue(x.Key, x.Select(y => y.Skip(1))));

    }

​

    private static NameSpace GroupNameSpaces(IEnumerable<RawValue> groups)

    {

        var result = new NameSpace();

        foreach (var group in groups)

            result.Add(group.Key, GroupNameSpaces(GetRawValues(group)));

        return result;

    }

​

    public class RawValue

    {

        public RawValue(string key, IEnumerable<IEnumerable<string>> values)

        {

            Key = key;

            Values = values;

        }

​

        public string Key

        {

            get;

            set;

        }

​

        public IEnumerable<IEnumerable<string>> Values

        {

            get;

            set;

        }

    }

​

    public class NameSpace : Dictionary<string, NameSpace>

    {

    }

}