private bool ContainsValue(Node currentNode, string value, int index)
{
if (currentNode == null)
return false;
if (currentNode.Value == value && currentNode.IsCompleteWord)
return true;
return ContainsValue(currentNode.Children[value[index]], value, index + 1);
}
private List<List<string>> FindAllAnagrams(Node root, Node currentNode, Dictionary<char, int> phraseDictionary, List<string> candidates)
{
var remainingChars = GetRemainingCharacters(phraseDictionary);
if (remainingChars.Count == 0 && currentNode.IsCompleteWord)
{
currentNode.IsUsed = true;
candidates.Add(currentNode.Value);
return new List<List<string>> { candidates };
}
if (remainingChars.Count == 0)
return null;
var allAnagrams = new List<List<string>>();
foreach (var character in remainingChars)
{
phraseDictionary[character]--;
if (currentNode.Children.ContainsKey(character) && !currentNode.Children[character].IsUsed)
{
var copy = candidates.ToList();
var anagrams = FindAllAnagrams(root, currentNode.Children[character], phraseDictionary, copy);
if (anagrams != null)
allAnagrams.AddRange(anagrams);
}
phraseDictionary[character]++;
}
if (IsCandidate(currentNode))
{
//Found a candidate word, search for next one
candidates.Add(currentNode.Value);
currentNode.IsUsed = true;
var anagrams = FindAllAnagrams(root, root, phraseDictionary, candidates);
if (anagrams != null)
allAnagrams.AddRange(anagrams);
}
foreach (var node in currentNode.Children.Values)
{
node.IsUsed = false;
}
return allAnagrams;
}
private void AddNode(Node currentNode, string value, int index)
{
if (currentNode.Value == value)
currentNode.IsCompleteWord = true;
if (index == value.Length)
return;
var key = value[index];
if (!currentNode.Children.ContainsKey(key))
{
var newNode = new Node(key, value.Substring(0, index + 1));
currentNode.Children.Add(key, newNode);
}
currentNode = currentNode.Children[key];
AddNode(currentNode, value, index + 1);
}
public Trie()
{
_root = new Node(' ', string.Empty);
}
private bool IsCandidate(Node node)
{
//add word to possible list if current node is complete word and:
//node is leaf
//node is not leaf but all children have been used
if (!node.IsCompleteWord)
return false;
if (node.Children.Keys.Count == 0 || node.Children.Values.Count == 0)
return true;
if (node.Children.Values.All(x => x.IsUsed))
return true;
return false;
}
