/// <summary>
/// A test harness for the LetterNode class.
/// </summary>
/// <param name="args"> The command line arguments passed in. </param>
public static void TestLetterNode(string[] args)
{
if (args.Length > 0)
{
LetterNode node = new LetterNode(args[0]);
for (int i = 1; i < args.Length; i++)
{
node.AddWord(args[i]);
}
Console.Write("Total words = " + node.LeafNodeCount());
Console.Write("Maximum word length = " + node.MaxLength());
}
else
{
Console.Write("Usage: GhostGame " + typeof(LetterNode).FullName + " <word-list>");
}
}
/// <summary>
/// Add a word to the dictionary if it meets two criteria:
/// <ul>
/// <li> The word must be at least MIN_WORD_LENGTH letters long.
/// <li> The word must not start with another valid word.
/// </ul>
/// The second criteria is enforced by the LetterNode class.
/// </summary>
/// <param name="word"> The word to add to the dictionary. </param>
private void AddWord(string word)
{
if (word.Length >= MIN_WORD_LENGTH)
{
char key = Convert.ToChar(word[0]);
LetterNode node = null;
if (_words.ContainsKey(key))
{
node = _words[key];
}
if (node == null)
{
_words[key] = new LetterNode(word);
}
else
{
node.AddWord(word);
}
}
}
/// <summary>
/// Add a word to the tree rooted at this node. This method implements
/// the Ghost rule that no word may begin with another word. That
/// requires two rules:
///
/// - If this node has no child nodes, the passed word begins with
/// this word and must not be added.
/// - If the passed word has a length of zero, this is the end of the
/// word and all child nodes must be deleted.
/// </summary>
/// <param name="word"> The word, or substring, to add to this node. </param>
public void AddWord(string word)
{
if (word[0] == _letter)
{
if (_nodes.Count > 0)
{
if (word.Length == 1)
{
_nodes.Clear();
}
else
{
char key = Convert.ToChar(word[1]);
LetterNode nextNode = null;
if (_nodes.ContainsKey(key))
{
nextNode = _nodes[key];
}
if (nextNode == null)
{
_nodes[key] = new LetterNode(word.Substring(1));
}
else
{
nextNode.AddWord(word.Substring(1));
}
}
}
}
else
{
throw new ArgumentException("Invalid first letter.");
}
}