PalindromeIndex -

PalindromeIndex1.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace theLoveLetterMstery
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = Convert.ToInt16(Console.ReadLine()); 

            for(int i=0;i<n;i++)
            {
                Console.WriteLine(indexPalindrome(Console.ReadLine())); 
            }

        }
        
        // 1 <  len < 100005
        public static int indexPalindrome(string s)
        {
            int len = s.Length;

            if (isPalindrome(s, -1))
                return -1; 
            for(int i = 0;i<len;i++)
            {
                if (isPalindrome(s, i))
                    return i;                
            }
            return -1; 
        }

        private static bool isPalindrome(string s, int index)
        {
            int len = s.Length;
            int start = 0;
            int end = len - 1;           

            while (start <= end)
            {
                if (start == index)
                    start++;
                else if (end == index)
                    end--;
                else if (s[start] == s[end])
                {
                    start++;
                    end--;
                }
                else
                    return false; 
            }
            return true; 
        }
    }
}