using System;

​

public class Program

{

    public static void Main()

    {       

        int[] arr = {1,2,3,4,5,6,7,8,9,10};

        int rank = GetRank(arr, 9);

        Console.WriteLine(rank);

    }

    private static int GetRank(int[] a, int search){

        return GetRank(a, search, 0, a.Length -1, 0, "-");

    }

    private static int GetRank(int[] a, int search, int lo, int hi, int deepLv, string printStyle = "+"){

        Console.WriteLine($"deeplv:{deepLv} lo:{lo} hi:{hi}");

        if(lo>hi) return -1;

        int mid = (lo + hi)/2;

        bool isPrintInclude = printStyle == "+";

        bool isPrintExclude = printStyle == "-";

        if(search > a[mid]) {

            if(isPrintInclude) 

                printList(a, mid+1, hi);

            else if(isPrintExclude) 

                printList(a, lo, mid-1);

            else 

                throw new Exception("err");

            return GetRank(a, search, mid+1, hi, deepLv + 1, printStyle);

        }else if(search< a[mid]) {

            if(isPrintInclude) 

                printList(a, lo, mid-1);

            else if(isPrintExclude) 

                printList(a, mid+1, hi);

            else 

                throw new Exception("err");

            return GetRank(a, search, lo, mid -1, deepLv + 1, printStyle);

        }

        else

        {

            return mid;

        }

    }

    private static void printList(int[] a, int lo, int hi){

        for(int i = lo; i <=hi; i ++){

            Console.Write(a[i] + " ");

        }

        Console.WriteLine("");

    }

}