using System;

using System.Linq;

using System.Collections.Generic;

using Moq.AutoMock;

using Moq;

using Moq.Protected;

​

public class Program

{

    public static void Main()

    {

        var a = DateTime.Now.AddYears(-5).AddMonths(4);

        var b = DateTime.Now.AddMonths(2);

        var ranges = Chunk(DateTime.Now.AddYears(-10), DateTime.Now.AddYears(2), 1).ToList();

        //var relevantRanges = ranges

        //  .Where(r => !(a < r.Start && b < r.Start))

        //  .Where(r => !(a > r.End && b > r.End));

        var relevantRanges2 = ranges

            .Where(r => r.Start < a || r.Start < b)

            .Where(r => r.End > a || r.End > b);

        var relevantRanges3 = ranges.Where(r => r.OverlapsWithRange(a, b));

        System.Console.WriteLine($"{a}->{b}");

        System.Console.WriteLine("----------------------------------");

        for (var i = 0; i < ranges.Count; ++i) {

            var newRange = "";

            if (relevantRanges3.Contains(ranges[i])) {

                var queryStart = ranges[i].Start > a ? ranges[i].Start : a;

                var queryEnd = ranges[i].End < b ? ranges[i].End : b;

                newRange = $" *** {queryStart}->{queryEnd}";

            }

            System.Console.WriteLine($"{i}: {ranges[i].Start}->{ranges[i].End}{newRange}");

        } 

    }

    public class TimeRange {

        public TimeRange(DateTime s, DateTime e) { Start = s; End = e; }

        public DateTime Start { get; set; }

        public DateTime End { get; set; }

        public bool OverlapsWithRange(DateTime start, DateTime end) =>

            (Start < start || Start < end) && (start < End || end < End);

    }

      private static IEnumerable<TimeRange> Chunk(DateTime start, DateTime end, int chunkSize = 1)

        {

            var chunkStart = start;

            var chunkEnd = start.AddYears(chunkSize).AddMilliseconds(-1);

            while (chunkEnd < end) {

                yield return new TimeRange(chunkStart, chunkEnd);

                chunkStart = chunkStart.AddYears(chunkSize);

                chunkEnd = chunkEnd.AddYears(chunkSize);

            }

            yield return new TimeRange(chunkStart, end);

        }

​

//5: 10/26/2015 18:44:14->10/26/2016 18:44:14 *** 02/26/2016 18:44:14->10/26/2016 18:44:14

//6: 10/26/2016 18:44:14->10/26/2017 18:44:14 *** 10/26/2016 18:44:14->10/26/2017 18:44:14

//7: 10/26/2017 18:44:14->10/26/2018 18:44:14 *** 10/26/2017 18:44:14->10/26/2018 18:44:14

//8: 10/26/2018 18:44:14->10/26/2019 18:44:14 *** 10/26/2018 18:44:14->10/26/2019 18:44:14

//9: 10/26/2019 18:44:14->10/26/2020 18:44:14 *** 10/26/2019 18:44:14->10/26/2020 18:44:14

//10: 10/26/2020 18:44:14->10/26/2021 18:44:14 *** 10/26/2020 18:44:14->12/26/2020 18:44:14

​

}

​