public TrieNode(char character, IDictionary<char, TrieNode> children, int wordCount, TrieNode parent)
{
this.Character = character;
this.Children = children;
this.WordCount = wordCount;
this.Parent = parent;
}
/// <summary>
/// Method to add word. Gets the first char of the word,
/// creates the child TrieNode if null, and recurses with the first
/// char removed from the word. If the word length is 0, return.
/// </summary>
private void AddWord(TrieNode trieNode, char[] word)
{
while (true)
{
if (word.Length == 0)
{
trieNode.WordCount++;
}
else
{
var firstChar = FirstChar(word);
TrieNode child;
trieNode.Children.TryGetValue(firstChar, out child);
if (child == null)
{
child = GetTrieNode(firstChar, trieNode);
trieNode.Children[firstChar] = child;
}
var characterRemoved = FirstCharRemoved(word);
trieNode = child;
word = characterRemoved;
continue;
}
break;
}
}
public Trie(TrieNode root)
{
this.root = root;
}
/// <summary>
/// Get a new TrieNode instance.
/// </summary>
/// <param name="character">Character of the TrieNode.</param>
private static TrieNode GetTrieNode(char character, TrieNode parent)
{
return new TrieNode(character, new Dictionary<char, TrieNode>(), 0, parent);
}
/// <summary>
/// Method to remove word. Remove only if node does not
/// have children and is not a word node and has a parent node.
/// </summary>
private void RemoveNode(TrieNode trieNode)
{
while (true)
{
// 1. should not have any children
// 2. should not be a word
// 3. do not remove root node
if (trieNode.Children.Count == 0 && !trieNode.IsWord && !Equals(trieNode, this.root))
{
var parent = trieNode.Parent;
trieNode.Parent.Children.Remove(trieNode.Character);
trieNode.Parent = null;
trieNode = parent;
continue;
}
break;
}
}
/// <summary>
/// Recursive method to get all the words starting from given TrieNode.
/// </summary>
private void GetWords(TrieNode trieNode, ICollection<string> words, StringBuilder buffer)
{
if (trieNode.IsWord)
{
words.Add(buffer.ToString());
}
foreach (var child in trieNode.Children.Values)
{
buffer.Append(child.Character);
this.GetWords(child, words, buffer);
// Remove recent character
buffer.Length--;
}
}
