using System;
using System.Text.RegularExpressions;
 
public class Test
{
	public static void Main()
	{
		string pattern = @"(?<=^(?:\d+(?:\.\d+)*|[A-Z]+))\.\s+";
        string[] strings = {
        	"1. Title1 Contains Space and Characters",
			"2. Title2 Contains Space and Characters",
			"2.1. Title2.1 Contains Space and Characters",
			"2.1.1.  Title2.1.1 Contains Space and Characters",
			"3.  Title3 Contains Space and Characters",
			"3.1.  Title3.1 Contains Space and Characters",
			"A.  Title A Contains Space and Characters",
			"B.  Title B Contains Space and Characters",
			"C.  Title C Contains Space and Characters",
			"Title which does not contains any Display Code"
        	};
        foreach(var s in strings)
		{
		    Array.ForEach(Regex.Split(s, pattern), Console.WriteLine);
		    Console.WriteLine("------");
		}
	}
}

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