07. Query Mess

using System;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;

class Program
{
    static void Main(string[] args)
    {
        string input = Console.ReadLine();

        while (input != "END")
        {
            StringBuilder build = RemoveSpaces(input);
            Dictionary<string, List<string>> data = GetCurrentFields(build.ToString());
            PrintCurrentResult(data);

            input = Console.ReadLine();
        }
    }

    static void PrintCurrentResult(Dictionary<string, List<string>> data)
    {
        foreach (var field in data)
        {
            Console.Write($"{field.Key}=[" + string.Join(", ", field.Value) + "]");
        }

        Console.WriteLine();
    }

    static Dictionary<string, List<string>> GetCurrentFields(string input)
    {
        Dictionary<string, List<string>> data = new Dictionary<string, List<string>>();
        MatchCollection matches = Regex.Matches(input, @"([^&=?]+)=([^&=?]+)");

        foreach (Match m in matches)
        {
            string field = m.Groups[1].Value.Trim();
            string value = m.Groups[2].Value.Trim();

            if (data.ContainsKey(field) == false)
            {
                data.Add(field, new List<string>());
            }
            data[field].Add(value);
        }

        return data;
    }

    static StringBuilder RemoveSpaces(string input)
    {
        StringBuilder build = new StringBuilder().Append(input);

        MatchCollection muchSpaces = Regex.Matches(input, @"(\+|%20| ){2,}");
        foreach (Match m in muchSpaces)
        {
            build.Replace(m.ToString(), " ");
        }

        MatchCollection space1 = Regex.Matches(build.ToString(), @"%20");
        MatchCollection space2 = Regex.Matches(build.ToString(), @"\+");

        for (int r = 0; r < space1.Count; r++)
        {
            build.Remove(build.ToString().IndexOf("%20"), 3);
        }
        for (int r = 0; r < space2.Count; r++)
        {
            build.Remove(build.ToString().IndexOf("+"), 1);
        }

        return build;
    }
}