private static List <string> SampleMatchingWords(WordRegexMatches wordRegexMatches)
{
byte[] wordMatches = wordRegexMatches.wordMatches;
int[] countsByRegex = wordRegexMatches.countsByRegex;
string[] selectedWords = new string[countsByRegex.Length];
// Examine regexes in order of increasing number of matching words
List <int> remainingRegexIndices = Enumerable.Range(0, countsByRegex.Length)
.OrderBy(regexIndex => countsByRegex[regexIndex]).ToList();
byte satisfiedRegexFlags = 0;
while (remainingRegexIndices.Count > 0)
{
int? matchedRegexIndex = null;
List <int> wordIndexChoices = new List <int>();
foreach (int ri in remainingRegexIndices)
{
for (int wi = 0; wi < ALL_WORDS.Length; wi++)
{
byte wm = wordMatches[wi];
byte regexFlag = (byte)(1 << ri);
// If wm matches this regex, and any other matches in wm overlap only
// with previously-matched regexes, then we found a new match
bool matchesThisRegex = (wm & regexFlag) != 0;
bool matchesOtherUnsatisfiedRegexes = (wm & ~regexFlag & ~satisfiedRegexFlags) != 0;
if (matchesThisRegex && !matchesOtherUnsatisfiedRegexes)
{
matchedRegexIndex = ri;
wordIndexChoices.Add(wi);
}
}
// Only accept choices from a single regex
if (matchedRegexIndex != null)
{
break;
}
}
if (matchedRegexIndex == null)
{
// This should never happen!
throw new System.Exception("No solution found for regexes!");
}
else
{
satisfiedRegexFlags |= (byte)(1 << matchedRegexIndex.Value);
remainingRegexIndices.Remove(matchedRegexIndex.Value);
selectedWords[matchedRegexIndex.Value] = ALL_WORDS[wordIndexChoices.PickRandom()];
}
}
return(selectedWords.ToList());
}
public static Puzzle SamplePuzzle(int rowNorth, int rowSouth, int colWest, int colEast)
{
// NW, NE, SE, SW
RegexData[] regexData = new RegexData[] {
RegexDataAtTablePos(rowNorth, colWest),
RegexDataAtTablePos(rowNorth, colEast),
RegexDataAtTablePos(rowSouth, colEast),
RegexDataAtTablePos(rowSouth, colWest),
};
WordRegexMatches wordRegexMatches = ComputeWordRegexMatches(regexData);
List <string> matchingWords = SampleMatchingWords(wordRegexMatches);
List <string> decoyWords = SampleDecoyWords(regexData);
return(new Puzzle(regexData.ToList(), matchingWords, decoyWords));
}