using System;

using System.Collections.Generic;

using NUnit.Framework;

public class Program

{

    public static void Main()

    {

            Assert.AreEqual("Thi1s is2 3a T4est", Kata.Order("is2 Thi1s T4est 3a"));

            Assert.AreEqual("Fo1r the2 g3ood 4of th5e pe6ople", Kata.Order("4of Fo1r pe6ople g3ood th5e the2"));

            Assert.AreEqual("", Kata.Order(""));

    }

}

​

public static class Kata

    {

        public static string Order(string words)

        {

            if (String.IsNullOrEmpty(words))

                return words;

            else

            {

                string[] word = words.Split(' ');

                string sentens = String.Empty;       

                Dictionary<int, string> sortedWords = new Dictionary<int, string>();

                foreach (string x in word)

                    for (int index = 0; index < x.Length; index++)

                        if (Char.IsDigit(x, index))

                            sortedWords.Add((int)Char.GetNumericValue(x,index), x);

                for (int index = 1; index < sortedWords.Count + 1; index++)

                    if (sortedWords.ContainsKey(index))

                        sentens += sortedWords[index] + " ";

              return sentens.TrimEnd();

            }

        }

    }

​

​