using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var mapChances = new Dictionary<string, double>();

        mapChances["A"] = 1;

        mapChances["B"] = 5;

        mapChances["C"] = 10;

        mapChances["D"] = 15;

        mapChances["E"] = 20;

        mapChances["F"] = 25;

        mapChances["G"] = 30;

        mapChances["H"] = 35;

        mapChances["I"] = 40;

        mapChances["J"] = 45;

        mapChances["K"] = 50;

        var results = new Dictionary<string, int>();

        for(var i=0; i<1_000_000; i++)

        {

            var r = CalculateRoundMap(mapChances);

            results.TryAdd(r, 0);

            results[r]++;

        }

        foreach(var kv in results.OrderBy(x => x.Value))

            Console.WriteLine($"{kv.Key}={kv.Value}");

        Console.WriteLine(results.Sum(x => x.Value));

    }

    private static string CalculateRoundMap(Dictionary<string, double> mapChances)

    {

        var total = mapChances.Values.Sum();

        var chances = Random.Shared.NextSingle() * total;

​

​

        foreach (var (map, chance) in mapChances)

        {

            if (chances < chance)

            {

                return map;

            }

​

            chances -= chance;

        }

​

        throw new InvalidOperationException();

    }

}