Beispiel #1
0
        private bool Attempt(Crossword crossword, CrosswordCell cell, IDictionary<CrosswordCell, List<char>> unresolvedCells)
        {
            var characters = unresolvedCells[cell];
            var questions = crossword.GetQuestionsForCell(cell).ToArray();
            foreach (var character in characters)
            {
                crossword.ApplyCharacter(cell, character);
                if (!CheckQuestions(crossword, questions))
                {
                    continue;
                }

                if (crossword.GetCells().All(c => crossword.GetCellCharacter(c) != 0))
                {
                    return true;
                }

                foreach (var affectedCell in crossword.GetQuestionsForCell(cell).SelectMany(crossword.GetCellsForQuestion).Where(c => crossword.GetCellCharacter(c) == 0))
                {
                    if (Attempt(crossword, affectedCell, unresolvedCells))
                    {
                        return true;
                    }
                }
            }

            crossword.ApplyCharacter(cell, '\0');
            return false;
        }
Beispiel #2
0
        public bool Solve(Crossword crossword)
        {
            var allLetters = GetAllLetters().ToArray();
            var unresolvedCells = crossword.GetCells().ToDictionary(cell => cell, cell => allLetters.ToList());
            while (true)
            {
                foreach (var unresolvedCell in unresolvedCells)
                {
                    var cell = unresolvedCell.Key;

                    var questions = crossword.GetQuestionsForCell(cell).ToArray();

                    var availableCharacters = unresolvedCell.Value;

                    foreach (var character in availableCharacters.ToArray())
                    {
                        crossword.ApplyCharacter(cell, character);
                        if (!CheckQuestions(crossword, questions))
                        {
                            availableCharacters.Remove(character);

                            if (availableCharacters.Count == 0)
                            {
                                throw new ArgumentException("Invalid crossword data", "crossword");
                            }
                        }
                    }

                    crossword.ApplyCharacter(cell, '\0');
                }

                var resolvedCellInfos = unresolvedCells.Where(info => info.Value.Count == 1).ToArray();
                if (resolvedCellInfos.Length == 0)
                {
                    break;
                }

                foreach (var cellInfo in resolvedCellInfos)
                {
                    crossword.ApplyCharacter(cellInfo.Key, cellInfo.Value[0]);
                    unresolvedCells.Remove(cellInfo.Key);
                }
            }

            if (unresolvedCells.Count == 0)
            {
                return true;
            }

            while (unresolvedCells.Count > 0)
            {
                var unrosolvedCell = unresolvedCells.First();
                if (!Attempt(crossword, unrosolvedCell.Key, unresolvedCells))
                    return false;
                unresolvedCells.Remove(unrosolvedCell.Key);
            }

            return true;
        }