private string[] Solve(WordRack originalRack, PrefixTreeNode root)
{
List <string> words = new List <string>();
foreach (char character in originalRack.AvailableLetters)
{
WordRack rack = originalRack.Clone();
PrefixTreeNode node = root.Children.FirstOrDefault(x => x.Letter == character);
if (node != null)
{
rack.Consume(character);
if (node.IsWord)
{
words.Add(node.GetWord());
}
string[] result = this.Solve(rack, node);
if (result != null && result.Length > 0)
{
words.AddRange(result);
}
}
}
return(words.ToArray());
}
public void Insert(string word)
{
if (word.Length == 0)
{
throw new ArgumentNullException("word");
}
_count++;
char[] characters = word.ToLower().ToCharArray();
PrefixTreeNode current = _root;
for (int index = 0; index < word.Length; index++)
{
PrefixTreeNode child = current.FindNode(characters[index]);
if (child != null)
{
current = child;
}
else
{
current.Children.Add(new PrefixTreeNode(current, characters[index]));
current = current.FindNode(characters[index]);
}
if (index == characters.Length - 1)
{
current.IsWord = true;
}
}
}
internal PrefixTreeNode(PrefixTreeNode parent, char letter)
{
_parent = parent;
_children = new List <PrefixTreeNode>();
_isWord = false;
_letter = letter;
}
public string GetWord()
{
List <char> sb = new List <char>();
sb.Add(_letter);
PrefixTreeNode parent = this.Parent;
while (parent != null && parent.Letter != '\0')
{
sb.Add(parent.Letter);
parent = parent.Parent;
}
return(new string(sb.Reverse <char>().ToArray()));
}
private bool IsMatch(string word, bool exact)
{
if (string.IsNullOrEmpty(word))
{
return(false);
}
PrefixTreeNode current = _root;
char[] letters = word.ToLowerInvariant().ToCharArray();
while (current != null)
{
for (int index = 0; index < letters.Length; index++)
{
if (current.FindNode(letters[index]) == null)
{
return(false);
}
current = current.FindNode(letters[index]);
}
return(exact ? (current.IsWord ? true : false) : true);
}
return(false);
}
public PrefixTree()
{
_root = new PrefixTreeNode(null, '\0');
}
