NoFlood.cs

private static void NoFlood(string _)
    {
        string value = String.Empty;
        int? cCList,cCPointer = null;
        int m = 0x0;
        string[] memoryStrings = new string[124];
        int counter = 0;

        char[] CharList = _.ToCharArray();

        for (int x = 0; x < CharList.Length; x++)
        {
            if(x == 0 )
            {
                //define
                {
                    cCList = CharList[x];
                    m = (int)cCList;
                    cCPointer = x;
                }
            }else if ( x > 0 )
            {
                cCList = m;
                if(CharList[x-1] == cCList)
                {
                    if(counter == 0 ) { value += CharList[x]; counter += 1;   }                    
                }
                else
                {
                    value += CharList[x];
                }
            } 
        }
        Console.WriteLine(value);
    }

NoFlood("aaaaaaaaaaaaaaaaaaaaaaaaaaa") returns (a)