using System;

using System.Numerics;              

​

public class Program

{

     public static char NextGreatestLetter(char[] letters, char target) {

         int len = letters.Length;

         int index = len / 2;

         int greaterIndex = -1;

         int state = 0 ;

         Console.WriteLine("Starting Index:" + index);

         int newIndex = -1;

         while(index >= 0){

            Console.WriteLine("Starting Loop Index:" + index);

            state =  letters[index].CompareTo(target);           

            Console.WriteLine("State:" + state);

            Console.WriteLine("Current Letter Is:" + letters[index]);

             if( state < 0 || state == 0){          

                 newIndex = ((letters.Length - index )/ 2) -1;                       

                 Console.WriteLine("New Index:" + newIndex);

                if(newIndex > 0){

                 index += newIndex;

                }else if (newIndex == 0){

                    index  = letters.Length - 1 ;

                    if( letters[index].CompareTo(target) <= 0 ) {

                        greaterIndex = -1;

                        index = -1;

                    }       

                    break;

                } if(newIndex < 0 ){

                    index = -1 ;

                }               

             }

             else if ( state > 0 ){

                 Console.WriteLine("Setting Greatest INDEX : " + index);

                 greaterIndex = index;      

                 newIndex = (( index )/ 2) -1 ; 

                 Console.WriteLine("New Index:" + newIndex);

                 if(newIndex == 0 || newIndex < 0 ){

                     index = 0 ;

                    if( letters[index].CompareTo(target) > 0 ) {

                        greaterIndex = -1;

                    }                    

                     break;

                 }else{

                    index = index - newIndex;

                 }

             }

         }

          Console.WriteLine("Last INDEX : " + index);

         if(index == -1 && greaterIndex == -1){

            Console.WriteLine(" Index: -1");

            index = 0 ;

         }else if(index == -1) {

             Console.WriteLine("GREATER INDEX : " + greaterIndex);

            index = greaterIndex;

         }else if(index !=greaterIndex && greaterIndex != -1){

            index = greaterIndex;

         }

         Console.WriteLine("FINISHED ");

         return letters[index];

    }

​

    public static void Main()

    {

        Console.WriteLine("Hello World");

        char[] letters = new char[] {'c', 'f', 'j'};

        char target = 'j';

        char answer = NextGreatestLetter(letters, target);

        Console.WriteLine("The Answer Is:");

        Console.WriteLine(answer);

    }

}