编辑代码

using System;
using System.Reflection;
using System.Text;

public class HelloWorld
{
    public static void Main()
    {
        var text = ModifyString("000101101000110011001111100110111101000110110101110101011");
        Console.WriteLine($"{text}");
    }
    private static string ModifyString(string input)
    {
        if (string.IsNullOrEmpty(input))
        {
            return input;
        }

        return string.Join(
            (string)input.Aggregate(new StringBuilder(), (sb, c) =>
            {
                switch (sb.Length)
                {
                    case > 0 when sb[^1] == c:
                        break;
                    case > 0:
                    {
                        var lastChar = sb[^1];
                        var consecutiveCount = 0;
                        for (var i = sb.Length - 1; i >= 0 && sb[i] == lastChar; i--) {
                            consecutiveCount++;
                        }

                        if(consecutiveCount < 3) {
                            sb.Remove(sb.Length - consecutiveCount, consecutiveCount);
                            sb.Append('0', consecutiveCount);
                        }

                        break;
                    }
                }
                sb.Append(c);
                return sb;
            }).ToString().AsEnumerable(), "");

        
    }
}