using System;

using System.Data;

using System.Linq;

using System.Collections.Generic;

using Newtonsoft.Json;

using System.Text.RegularExpressions;

using System.Dynamic;

using System.IO;

public class Program

{

    public static void Main()

    {

        var a = DateTime.Parse("2022/11/01");

        var b = DateTime.Parse("2023/01/03");

​

        var tmp1 = ( from r in   Enumerable.Range(0, (b-a).Days+1)

                    let startDate = a.AddDays(r)

                   select new {

                       startDate = startDate,

                       year = startDate.Year

                    }).ToList();

        var tmp1c = (from r in tmp1

                    group r by r.year into G

                      select new {

                          Year = G.Key,

                          Rangs = G.Select((data, index) => new { idx=index, startDate=data.startDate }).ToList()

                      }).ToList();

        var tmp2c = (from r in tmp1c

                    select new {

                      r.Year,

                      RangeList = (    (from x in ( from r2 in r.Rangs

                                                      select new 

                                                     {

                                                         startDate = r2.startDate,

                                                         idx = r2.idx,

                                                         grp = (int) ( r2.idx/2)

                                                     })

                                          group x by x.grp into G2

                                           let  startDate = G2.Select(o=>o.startDate).ToList()[0]

                                            let  endDate = G2.Select(o=>o.startDate).ToList().Count> 1 ?  G2.Select(o=>o.startDate).ToList()[1] :startDate

                                          select new { startDate,endDate } ).ToList()

                                     )

                    }).ToList();

        var tmp3c = tmp2c.SelectMany(o=>o.RangeList);

        Console.WriteLine($"{JsonConvert.SerializeObject(tmp3c, Formatting.Indented)}");    

​

        /*

        var tmp1_year = ( from r in tmp1

                         group r by r.year into G

                         select new {

                           Year=    G.Key,

                           Ranges=  (    (from x in ( from r2 in G

                                                      select new 

                                                     {

                                                         startDate = r2.startDate,

                                                         idx = r2.idx,

                                                         grp = (int) ( r2.idx/2)

                                                     })

                                          group x by x.grp into G2

                                           let  startDate = G2.Select(o=>o.startDate).ToList()[0]

                                            let  endDate = G2.Select(o=>o.startDate).ToList().Count> 1 ?  G2.Select(o=>o.startDate).ToList()[1] :startDate

                                          select new { startDate,endDate } ).ToList()

                                     )

                         }

                        ).ToList();

        var tmpResult = tmp1_year.SelectMany(o=>o.Ranges).ToList();

        Console.WriteLine($"{JsonConvert.SerializeObject(tmpResult, Formatting.Indented)}");    

​

       */

        /*

        var tmp2 = (from r in tmp1

                   group r by new {r.grp, r.year} into G

                    let  startDate = G.Select(o=>o.startDate).ToList()[0]

                    let  endDate = G.Select(o=>o.startDate).ToList().Count> 1 ?  G.Select(o=>o.startDate).ToList()[1] : DateTime.MinValue

                   select new { 

                      //grp = G.Key,

                     startDate,

                      endDate =endDate.Year != startDate.Year ? startDate : endDate

                    }).ToList();

        foreach(var item in tmp2)

        {

​

            Console.WriteLine($"{JsonConvert.SerializeObject(item, Formatting.Indented)}"); 

        }*/

    }

    public class TestObj{

       public string KEY1 {get;set;}

       public string KEY2 {get;set;}

    }

}

​

​