using System;
using System.Linq;
using System.Collections.Generic;
using System.Globalization;
 
public class Test
{
	public static void Main()
	{
	   var datesList = new List<DateTime>() { 
                new DateTime(2013,1,1),new DateTime(2013,8,1),new DateTime(2013,10,1),
                new DateTime(2013,1,15),new DateTime(2013,1,22),new DateTime(2013,1,28),
                new DateTime(2013,2,10),new DateTime(2013,2,11),new DateTime(2013,2,22),
            };
        var abRotations = datesList
            .GroupBy(d => CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(d, CalendarWeekRule.FirstDay, DayOfWeek.Monday))
            .Select((wg, i) => new { WeekGroup = wg, Index = i })
            .GroupBy(x => x.Index % 2);
 
        List<DateTime> A_Rotation = abRotations.First().SelectMany(x => x.WeekGroup).ToList();
        List<DateTime> B_Rotation = abRotations.Last().SelectMany(x => x.WeekGroup).ToList();
 
        Console.WriteLine("A-Rotation weeks: " + A_Rotation.Count);
        foreach (DateTime aDate in A_Rotation)
            Console.WriteLine(aDate.ToString());
        Console.WriteLine("B-Rotation weeks: " + B_Rotation.Count);
        foreach (DateTime bDate in B_Rotation)
            Console.WriteLine(bDate.ToString());
 
	}   
}
 
 
 

dXNpbmcgU3lzdGVtOwp1c2luZyBTeXN0ZW0uTGlucTsKdXNpbmcgU3lzdGVtLkNvbGxlY3Rpb25zLkdlbmVyaWM7CnVzaW5nIFN5c3RlbS5HbG9iYWxpemF0aW9uOwoKcHVibGljIGNsYXNzIFRlc3QKewoJcHVibGljIHN0YXRpYyB2b2lkIE1haW4oKQoJewoJICAgdmFyIGRhdGVzTGlzdCA9IG5ldyBMaXN0PERhdGVUaW1lPigpIHsgCiAgICAgICAgICAgICAgICBuZXcgRGF0ZVRpbWUoMjAxMywxLDEpLG5ldyBEYXRlVGltZSgyMDEzLDgsMSksbmV3IERhdGVUaW1lKDIwMTMsMTAsMSksCiAgICAgICAgICAgICAgICBuZXcgRGF0ZVRpbWUoMjAxMywxLDE1KSxuZXcgRGF0ZVRpbWUoMjAxMywxLDIyKSxuZXcgRGF0ZVRpbWUoMjAxMywxLDI4KSwKICAgICAgICAgICAgICAgIG5ldyBEYXRlVGltZSgyMDEzLDIsMTApLG5ldyBEYXRlVGltZSgyMDEzLDIsMTEpLG5ldyBEYXRlVGltZSgyMDEzLDIsMjIpLAogICAgICAgICAgICB9OwogICAgICAgIHZhciBhYlJvdGF0aW9ucyA9IGRhdGVzTGlzdAogICAgICAgICAgICAuR3JvdXBCeShkID0+IEN1bHR1cmVJbmZvLkN1cnJlbnRDdWx0dXJlLkNhbGVuZGFyLkdldFdlZWtPZlllYXIoZCwgQ2FsZW5kYXJXZWVrUnVsZS5GaXJzdERheSwgRGF5T2ZXZWVrLk1vbmRheSkpCiAgICAgICAgICAgIC5TZWxlY3QoKHdnLCBpKSA9PiBuZXcgeyBXZWVrR3JvdXAgPSB3ZywgSW5kZXggPSBpIH0pCiAgICAgICAgICAgIC5Hcm91cEJ5KHggPT4geC5JbmRleCAlIDIpOwogICAgCiAgICAgICAgTGlzdDxEYXRlVGltZT4gQV9Sb3RhdGlvbiA9IGFiUm90YXRpb25zLkZpcnN0KCkuU2VsZWN0TWFueSh4ID0+IHguV2Vla0dyb3VwKS5Ub0xpc3QoKTsKICAgICAgICBMaXN0PERhdGVUaW1lPiBCX1JvdGF0aW9uID0gYWJSb3RhdGlvbnMuTGFzdCgpLlNlbGVjdE1hbnkoeCA9PiB4LldlZWtHcm91cCkuVG9MaXN0KCk7CgogICAgICAgIENvbnNvbGUuV3JpdGVMaW5lKCJBLVJvdGF0aW9uIHdlZWtzOiAiICsgQV9Sb3RhdGlvbi5Db3VudCk7CiAgICAgICAgZm9yZWFjaCAoRGF0ZVRpbWUgYURhdGUgaW4gQV9Sb3RhdGlvbikKICAgICAgICAgICAgQ29uc29sZS5Xcml0ZUxpbmUoYURhdGUuVG9TdHJpbmcoKSk7CiAgICAgICAgQ29uc29sZS5Xcml0ZUxpbmUoIkItUm90YXRpb24gd2Vla3M6ICIgKyBCX1JvdGF0aW9uLkNvdW50KTsKICAgICAgICBmb3JlYWNoIChEYXRlVGltZSBiRGF0ZSBpbiBCX1JvdGF0aW9uKQogICAgICAgICAgICBDb25zb2xlLldyaXRlTGluZShiRGF0ZS5Ub1N0cmluZygpKTsKCgl9ICAgCn0KCiAgICAK