using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("********* First Example *********");

        Console.WriteLine("##### Result = {0} #####", LadderLength("hit", "cog", new List<string>{"hot","dot","dog","lot","log","cog"}));

        Console.WriteLine("\n\n********* Second Example *********");

        Console.WriteLine("##### Result = {0} #####",LadderLength("hit", "cog", new List<string>{"hot","dot","dog","lot","log"}));

    }

    static int LadderLength(string beginWord, string endWord, IList<string> wordList) {

        var foundSet = new HashSet<string>();

        var wordSet = new HashSet<string>(wordList);

        foundSet.Add(beginWord);

        int distance = 1;

        while (!foundSet.Contains(endWord))

        {

            var toAdd = new HashSet<string>();

            foreach(var w in foundSet)

            {

                Console.WriteLine("Distance = {0}, word = {1}", distance, w);

                for(int i = 0; i < w.Length; i++)

                {

                    char[] chars = w.ToCharArray();

                    for(char c = 'a'; c <= 'z'; c++)

                    {

                        chars[i] = c;

                        string word = new String(chars);

                        if(wordSet.Contains(word))

                        {

                            if(word == endWord)

                                return ++distance;

                            toAdd.Add(word);    

                            wordSet.Remove(word);

                            Console.WriteLine(word);

                        }

                    }

                }

            }

            distance++;

            if(toAdd.Count == 0)

                return 0;

            foundSet = toAdd;

        }

        return distance;

    }

}