/// <summary>
/// Solve the puzzle and output the found words to the results pane.
/// </summary>
private void Solve()
{
// Get distinct characters entered into TextBoxes
HashSet<char> enteredCharacters = new HashSet<char>(_textboxes.SelectMany(textBox => textBox.Text).Distinct());
// Filter words by the entered characters
var filteredWords = _allWords.Where(word => word.ToCharArray().Distinct().All(character => enteredCharacters.Contains(character)));
Trie filteredLexicon = new Trie(filteredWords);
List<string> foundWords = new List<string>();
for (int i = 0; i < 16; i++)
{
bool[] visited = new bool[16];
FindWords(i, string.Empty, visited, filteredLexicon, foundWords);
}
var words = foundWords.Distinct().OrderByDescending(w => w.Length);
txtResults.Text = string.Format("Found {0} words:" + Environment.NewLine, words.Count());
txtResults.Text += string.Join(Environment.NewLine, words);
}
/// <summary>
/// Recursively find words starting from the specified box.
/// </summary>
/// <param name="box">Starting box.</param>
/// <param name="prefix">Prefix for the current word.</param>
/// <param name="visited">Indicates which boxes have already been visited for this path.</param>
/// <param name="lexicon">Lexicon of words to search.</param>
/// <param name="foundWords">List in which to add found words.</param>
private void FindWords(int box, string prefix, bool[] visited, Trie lexicon, List<string> foundWords)
{
visited[box] = true;
string possibleWord = prefix + _textboxes[box].Text;
bool isPrefix;
bool isWord = lexicon.Contains(possibleWord, out isPrefix);
if (!isPrefix) // No possible words based on this path, so abort
return;
if (possibleWord.Length >= MIN_WORD_LENGTH && isWord)
{
foundWords.Add(possibleWord);
}
// Visit children that haven't already been visited
foreach (int child in _adjacent[box].Where(x => !visited[x]))
{
bool[] newVisited = new bool[16];
visited.CopyTo(newVisited, 0);
FindWords(child, possibleWord, newVisited, lexicon, foundWords);
}
}
