private static void _MatchRecursive(Node node, ISet<string> rtn, string letters, string prefix, int? maxMatches)
{
if (maxMatches != null && rtn.Count == maxMatches)
return;
if (node == null)
{
if (!rtn.Contains(letters)) rtn.Add(letters);
return;
}
letters += node.Letter.ToString();
if (prefix.Length > 0)
{
if (node.ContainsKey(prefix[0]))
{
_MatchRecursive(node[prefix[0]], rtn, letters, prefix.Remove(0, 1), maxMatches);
}
}
else
{
foreach (char key in node.Keys)
{
_MatchRecursive(node[key], rtn, letters, prefix, maxMatches);
}
}
}
//Find a node given the key("Jo")
public static bool Find(Node node, string key)
{
//Is key empty
if (string.IsNullOrEmpty(key))
return true;//terminal Node
//get the first character
string first = key.Substring(0, 1);
//get the tail: key - first character
string tail = key.Substring(1);
Node curNode = node.Children.GetNodeByKey(first);
//loop until you locate the key i.e. "Jo"
if (curNode != null)
{
return Find(curNode, tail);
}
else
{
//not found, return false
return false;
}
}
//Locates a node based on the key; eg. Locates "Jo" node on the tree
public static Node GetChildNode(Node node, string key)
{
//Is key empty
if (string.IsNullOrEmpty(key))
return node;//terminal Node?
//get the first character
string first = key.Substring(0, 1);
//get the tail: key - first character
string tail = key.Substring(1);
//current node
Node curNode = node.Children.GetNodeByKey(first);
//loop until you locate the key i.e. "Jo"
if (curNode != null)
{
return GetChildNode(curNode, tail);
}
else
{
//not found, return null
return null;
}
}
//Adds a node into the children list
public void Add(Node node)
{
//cannot readd a same node
if (_owner.IsParentOrChild(node))
throw new InvalidOperationException("Cannot add an ancestor or descendant.");
_children.Add(node);
node.Parent = _owner;
}
private void InnerAddWord(string wordSubString, Node element)
{
if (string.IsNullOrEmpty(wordSubString) || string.IsNullOrWhiteSpace(wordSubString))
{
element.Occurances++;
return;
}
var currChar = wordSubString[0].ToString();
if (!element.Children.ContainsKey(currChar))
{
element.Children.Add(currChar, new Node(currChar) { Parent = element });
}
this.InnerAddWord(wordSubString.Substring(1), element.Children[currChar]);
}
public static void Insert(Node root, string word)
{
if (String.IsNullOrWhiteSpace(word))
return;
int index;
var crawler = root;
for (int level = 0; level < word.Length; level++)
{
index = char_to_index(word[level]);
if (crawler.CharList[index] == null)
crawler.CharList[index] = new Node();
crawler = crawler.CharList[index];
}
crawler.IsLeaf = true;
}
public static bool Search(Node root, string word)
{
if (string.IsNullOrWhiteSpace(word))
return false;
int index;
var crawler = root;
for (int i = 0; i < word.Length; i++)
{
index = char_to_index(word[i]);
if (crawler.CharList[index] == null)
return false;
crawler = crawler.CharList[index];
}
return (crawler != null && crawler.IsLeaf);
}
private bool InnerTryFindWord(string wordSubString, out int occurances, Node element)
{
if (string.IsNullOrEmpty(wordSubString) || string.IsNullOrWhiteSpace(wordSubString))
{
occurances = element.Occurances;
return true;
}
var currChar = wordSubString[0].ToString();
if (!element.Children.ContainsKey(currChar))
{
occurances = 0;
return false;
}
return this.InnerTryFindWord(wordSubString.Substring(1), out occurances, element.Children[currChar]);
}
/* Gets all the childern starting from a string
ex: returns all names starting from Jo -> John, Joe, Joseph etc*/
public static void GetChildrenStartingFromKey(Node node, string key)
{
//Get the node which has the value of "Jo"
Node curNode = GetChildNode(node, key);
//if "Jo" found:
if (curNode != null)
{
//get the children of "Jo" -> John, Joe, Joseph etc
IEnumerator iterator = curNode.GetDepthNodes();
while (iterator.MoveNext())
{
//get child
Node childNode = (Node)iterator.Current;
//Does child have a valid full name
if (childNode.IsTerminal)
Console.WriteLine(childNode.Value);
}
}
}
public Trie()
{
this.root = new Node("");
}
//Removes a node
public void Remove(Node node)
{
_children.Remove(node);
node.Parent = null;
}
public TrieFilter()
{
RootNode = new Node { Letter = Node.Root };
}
static void Main(string[] args)
{
//Root Node
Node root = new Node("", "");
//Loads Names
TextReader reader;
string textLine;
try
{
reader = new StreamReader(@"..\..\names.txt");
while ((textLine = reader.ReadLine()) != null)
{
root = Trie.InsertNode(textLine, root);
}
reader.Close();
}
catch (Exception ex)
{
Console.WriteLine("Error Opening File: " + ex.Message);
}
Console.WriteLine("Enter Option");
Console.WriteLine("-------------------------------------");
Console.WriteLine("1. DFS on Trie");
Console.WriteLine("2. BFS on Trie");
Console.WriteLine("3. Find a Name on the Directory");
Console.WriteLine("4. Directory Lookup");
Console.WriteLine("5. Exit");
Console.WriteLine("--------------------------------------");
Console.Write("Enter Option:");
int option = int.Parse(Console.ReadLine());
switch (option)
{
case 1:
IEnumerator iterator = root.GetDepthNodes();
while (iterator.MoveNext())
{
Node n = (Node)iterator.Current;
Console.WriteLine(n.Value);
}
break;
case 2:
IEnumerator iterator2 = root.GetBreadthNodes();
while (iterator2.MoveNext())
{
Node n = (Node)iterator2.Current;
Console.WriteLine(n.Value);
}
break;
case 3:
Console.Write("Enter Name to Find(Case Sensitive):");
string name = Console.ReadLine();
bool fnd = Trie.Find(root, name);
if (fnd)
Console.WriteLine("Found");
else
Console.WriteLine("Not Found");
break;
case 4:
Console.Write("Enter Name to Lookup(Case Sensitive):");
string name2 = Console.ReadLine();
Trie.GetChildrenStartingFromKey(root, name2);
break;
}
Console.WriteLine("--------------------------------------");
Console.WriteLine("Press any key to exit!");
Console.ReadLine();
}
internal NodeCollection(Node owner)
{
if (null == owner) throw new ArgumentNullException("Owner");
_owner = owner;
}
//determines if this node shares hierarchy with given node
public bool IsParentOrChild(Node node)
{
if (node == this) return true;
if (this.IsParentOfNode(node)) return true;
if (this.IsChildOfNode(node)) return true;
return false;
}
//Determins if this node is ancestor of the given node
public bool IsParentOfNode(Node node)
{
if (_children.Contains(node)) return true;
foreach (Node childNode in _children)
if (childNode.IsParentOfNode(node)) return true;
return false;
}
//Determins if this node is descendant of the given node
public bool IsChildOfNode(Node node)
{
if (null == _parent) return false;
if (node == _parent) return true;
return _parent.IsChildOfNode(node);
}
//Inserts Names into the Trie data structure
public static Node InsertNode(string name, Node root)
{
//Is name null?
if (string.IsNullOrEmpty(name))
throw new ArgumentNullException("Null Key");
//set the index, start inserting characters
int index = 1;
//key
string key;
//start with the root node
Node currentNode = root;
//loop for all charecters in the name
while (index <= name.Length)
{
//get the key character
key = name[index - 1].ToString();
//does the node with same key already exist?
Node resultNode = currentNode.Children.GetNodeByKey(key);
//No, this is a new key
if (resultNode == null)
{
//Add a node
Node newNode = new Node(key, name.Substring(0, index));
//If reached the last charaecter, this is a valid full name
if (index == name.Length)
newNode.IsTerminal = true;
//add the node to currentNode(i.e. Root node for the first time)
currentNode.Children.Add(newNode);
//set as the current node
currentNode = newNode;
}
else
{
//node already exist, set as tghe current node
//and move to the next character in the name
currentNode = resultNode;
}
//move to the next character in the name
index++;
}
//all done, return root node
return root;
}
//Determins if the children contains a node, test for equality
public bool Contains(Node node)
{
return _children.Contains(node);
}
