namespace WhiteRabbit { using System; using System.Collections.Concurrent; using System.Collections.Generic; using System.Configuration; using System.Diagnostics; using System.Linq; using System.Numerics; using System.Text; /// /// Main class /// public static class Program { /// /// Main entry point /// public static void Main() { var stopwatch = new Stopwatch(); stopwatch.Start(); var sourcePhrase = ConfigurationManager.AppSettings["SourcePhrase"]; var sourceChars = ToOrderedChars(sourcePhrase); var maxWordsInPhrase = int.Parse(ConfigurationManager.AppSettings["MaxWordsInPhrase"]); if (sourceChars.Length + maxWordsInPhrase > 27) { Console.WriteLine("Only anagrams of up to 27 characters are allowed"); return; } if (!BitConverter.IsLittleEndian) { Console.WriteLine("Only little-endian systems are supported due to MD5Digest optimizations"); return; } if (IntPtr.Size != 8) { Console.WriteLine("Only 64-bit systems are supported due to MD5Digest optimizations"); return; } if (Vector.Count != 4) { Console.WriteLine("Only 128-bit SSE systems are supported due to MD5Digest optimizations"); } var expectedHashesAsVectors = ConfigurationManager.AppSettings["ExpectedHashes"] .Split(',') .Select(hash => new Vector(HexadecimalStringToUnsignedIntArray(hash))) .ToArray(); #if DEBUG var anagramsBag = new ConcurrentBag(); #endif var processor = new StringsProcessor( Encoding.ASCII.GetBytes(sourcePhrase), maxWordsInPhrase, ReadInput()); Console.WriteLine($"Initialization complete; time from start: {stopwatch.Elapsed}"); stopwatch.Restart(); processor.GeneratePhrases() .ForAll(phraseBytes => { Debug.Assert( sourceChars == ToOrderedChars(ToString(phraseBytes)), $"StringsProcessor produced incorrect anagram: {ToString(phraseBytes)}"); var hashVector = ComputeHashVector(phraseBytes); if (Array.IndexOf(expectedHashesAsVectors, hashVector) >= 0) { var phrase = ToString(phraseBytes); var hash = VectorToHexadecimalString(hashVector); Console.WriteLine($"Found phrase for {hash}: {phrase}; time from start is {stopwatch.Elapsed}"); } #if DEBUG anagramsBag.Add(ToString(phraseBytes)); #endif }); Console.WriteLine($"Done; time from start: {stopwatch.Elapsed}"); #if DEBUG var anagramsArray = anagramsBag.ToArray(); var anagramsSet = new HashSet(anagramsArray); Array.Sort(anagramsArray); Console.WriteLine("All anagrams:"); for (var i = 0; i < anagramsArray.Length; i++) { Console.WriteLine(anagramsArray[i]); } // Duplicate anagrams are expected, as e.g. "norway spoils tut tut" will be taken twice: // as "norway1 spoils2 tut3 tut4" and "norway1 spoils2 tut4 tut3" // (in addition to e.g. "norway1 tut3 spoils2 tut4") Console.WriteLine($"Total anagrams count: {anagramsArray.Length}; unique anagrams: {anagramsSet.Count}; time from start: {stopwatch.Elapsed}"); #endif } // Code taken from http://stackoverflow.com/a/321404/831314 private static uint[] HexadecimalStringToUnsignedIntArray(string hex) { return Enumerable.Range(0, hex.Length) .Where(x => x % 8 == 0) .Select(x => ChangeEndianness(hex.Substring(x, 8))) .Select(hexLe => Convert.ToUInt32(hexLe, 16)) .ToArray(); } // Bouncy Castle is used instead of standard .NET methods for performance reasons private static Vector ComputeHashVector(Phrase input) { return new Vector(MD5Digest.Compute(input)); } private static string VectorToHexadecimalString(Vector hash) { var components = Enumerable.Range(0, 4) .Select(i => hash[i].ToString("x8")) .Select(ChangeEndianness); return string.Concat(components); } private static string ChangeEndianness(string hex) { return hex.Substring(6, 2) + hex.Substring(4, 2) + hex.Substring(2, 2) + hex.Substring(0, 2); } private static string ToString(Phrase phrase) { return Encoding.ASCII.GetString(phrase.GetBytes()); } private static IEnumerable ReadInput() { string line; while ((line = Console.ReadLine()) != null) { yield return Encoding.ASCII.GetBytes(line); } } private static string ToOrderedChars(string source) { return new string(source.Where(ch => ch != ' ').OrderBy(ch => ch).ToArray()); } #if SINGLE_THREADED private static void ForAll(this IEnumerable source, Action action) { foreach (var entry in source) { action(entry); } } #endif } }