the Love-Letter Mystery

James found a love letter that his friend Harry has written to his girlfriend. James is a prankster, so he decides to meddle with the letter. He changes all the words in the letter into palindromes.

To do this, he follows two rules:

1. He can only reduce the value of a letter by , i.e. he can change d to c, but he cannot change c to d or d to b.
2. The letter a may not be reduced any further.

Each reduction in the value of any letter is counted as a single operation. Find the minimum number of operations required to convert a given string into a palindrome.

For example, given the string , the following two operations are performed: cde → cdd → cdc

Question from hackerrank.

Solution in C# - 

class Solution {

    static int theLoveLetterMystery(string s) {    

        int ans = 0;

        int len = s.Length/2;

        string s1 = s.Substring(0,len);

        string s2 = s.Substring(len);

        //Console.WriteLine(s1+" "+s2);

        for(int i=0, j=s2.Length-1 ; i<s1.Length && j>=0 ; i++, j--)

        {

            ans += Math.Abs(s1[i]-s2[j]);

        }        

        return ans;

    }

    static void Main(string[] args) {

        TextWriter textWriter = new StreamWriter(@System.Environment.GetEnvironmentVariable("OUTPUT_PATH"), true);

        int q = Convert.ToInt32(Console.ReadLine());

        for (int qItr = 0; qItr < q; qItr++) {

            string s = Console.ReadLine();

            int result = theLoveLetterMystery(s);

            textWriter.WriteLine(result);

        }

        textWriter.Flush();

        textWriter.Close();

    }

}