QueryMess / Regex / Softuni

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

class QueryMess
{
    static void Main()
    {
        // regex patterns
        string pattern = @"([^&=?]*)=([^&=]*)";
        string regex = @"((%20|\+)+)";

        // input and matching
        string inputLine;

        while (!((inputLine = Console.ReadLine()) == "END"))
        {
            Regex pairs = new Regex(pattern);
            MatchCollection matches = pairs.Matches(inputLine);

            // storing matching fields and values into a dictionary, per line of input
            Dictionary<string, List<string>> results = new Dictionary<string, List<string>>();
            for (int i = 0; i < matches.Count; i++)
            {
                string field = matches[i].Groups[1].Value;
                field = Regex.Replace(field, regex, word => " ").Trim();

                string value = matches[i].Groups[2].Value;
                value = Regex.Replace(value, regex, word => " ").Trim();

                if (!results.ContainsKey(field))
                {
                    List<string> values = new List<string>();
                    values.Add(value);
                    results.Add(field, values);
                }
                else if (results.ContainsKey(field))
                {
                    results[field].Add(value);
                }
            }

            // printing
            foreach (var pair in results)
            {
                Console.Write("{0}=[{1}]", pair.Key, string.Join(", ", pair.Value));
            }
            Console.WriteLine();
        }
    }
}