using System;

using System.Text.RegularExpressions;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        List<double> arr = new List<double> { 5, 10, 7, 15, 9, 21, 1 };

        var rankDict = arr.OrderByDescending(num=>num)

            .Select((number, index) => new {Number = number, Rank = index})

            .ToDictionary(m => m.Number, m => m.Rank);

        var rankedArray = new List<double>();

        foreach(var num in arr)

        {

            rankedArray.Add(rankDict[num] + 1);

        }

        Console.WriteLine(string.Join("-", rankedArray));

    }

}