using System;

public class Program

{

    public static void Main()

    {

        var np1 = "Hello";

        Console.WriteLine(np1.Length/2); // integer division

        Console.WriteLine("help".IsPalindrome());

        Console.WriteLine("deed".IsPalindrome());

        Console.WriteLine("deeeeeed".IsPalindrome());

        Console.WriteLine("dee ee eed".IsPalindrome());

        Console.WriteLine("Dee eee eed".IsPalindrome());

        Console.WriteLine("taco Cat".IsPalindrome());

    }

}

​

​

public static class PalindromeExtension {

    public static bool IsPalindrome(this string astring) {

        astring = astring.Trim().Replace(" ","").ToLowerInvariant();

        if (string.IsNullOrEmpty(astring)){

            return false;

        }

        string front;

        string back;

        // if num chars is even, then first half and second half must be mirror

        if (astring.Length % 2 == 0) {

            front = astring.Substring(0,astring.Length/2);

            back = astring.Substring(astring.Length/2);

            Console.WriteLine($"front {front} back {back}");

            return front.ReverseCompare(back);

        }

        front = astring.Substring(0,astring.Length/2);

        back = astring.Substring(astring.Length/2+1);

        Console.WriteLine($"front {front} back {back}");

        return front.ReverseCompare(back);

    }

    public static bool ReverseCompare(this string left, string right) {

        for (int i = 0; i < left.Length; i++){

            if (left[i] != right[right.Length-1-i]) { return false; }

        }

        return true;

    }

    public static string FindLongestPalindrome(this string s){

        if (string.IsNullOrEmpty(s)){

            return "";

        }

         if (s.IsPalindrome()){ return s; }

    }

}

​