// Returns all values whose key begin with k
public List <ValueType> AutoComplete(String key)
{
var result = new List <ValueType>();
TrieNodeArray <ValueType> tmpNode = null;
var currentNode = root;
// iterate characters of key
for (int i = 0; i < key.Length; i++)
{
char ch = key[i];
// if we find a child node with key matching character
if ((tmpNode = currentNode.FindChildNode(ch)) != null)
{
// set our current node as child node
currentNode = tmpNode;
// if we are on the last character
// return all terminal nodes from this node
if (i == (key.Length - 1))
{
foreach (var node in currentNode.TerminalNodes())
{
result.Add(node.Value);
}
}
}
}
return(result);
}
public TrieNodeArray()
{
Character = default(char);
Parent = null;
Children = new TrieNodeArray <ValueType> [MAXCHARS];
Value = default(ValueType);
}
// Adds the node to first available child node
// adds optional value if its the last character
public void AddToChildren(TrieNodeArray <ValueType> node, ValueType value = default(ValueType))
{
for (int i = 0; i < Children.Length; i++)
{
if (Children[i] == null)
{
Children[i] = node;
Children[i].Value = value;
break;
}
}
}
// Removes key/value pair from Trie
// Returns true if successful
public bool Remove(String key)
{
var currentNode = root;
TrieNodeArray <ValueType> tmpNode = null;
for (int i = 0; i < key.Length; i++)
{
char ch = key[i];
if ((tmpNode = currentNode.FindChildNode(ch)) != null)
{
// we are on the last character of the key
// and the is a child node that is terminal
if ((i == (key.Length - 1)) && (tmpNode.Value != null))
{
tmpNode.Remove();
return(true);
}
}
currentNode = tmpNode;
}
return(false);
}
// Returns value v that corresponds to full key k
public ValueType Translate(String key)
{
var currentNode = root;
TrieNodeArray <ValueType> tmpNode = null;
// iterate characters of key
for (int i = 0; i < key.Length; i++)
{
char ch = key[i];
if ((tmpNode = currentNode.FindChildNode(ch)) != null)
{
// if we are on last character and child node exists thats terminal
if ((i == (key.Length - 1)) && (tmpNode.Value != null))
{
// return the value of this child node
return(tmpNode.Value);
}
currentNode = tmpNode;
}
}
return(default(ValueType));
}
// Add key/value pair to Trie
// Update value if key already exists
public void AddWord(String key, ValueType value)
{
// key must be something!
if (key == null)
{
throw new ArgumentException("key cannot be null");
}
// value must be something!
if (value == null)
{
throw new ArgumentException("value cannot be null");
}
TrieNodeArray <ValueType> currentNode = root;
TrieNodeArray <ValueType> tmpNode = null;
// iterate through each key character
for (int i = 0; i < key.Length; i++)
{
char ch = key[i];
// iterate through each child of currentNode
for (int j = 0; j < currentNode.Children.Length; j++)
{
// node exists, follow the path
TrieNodeArray <ValueType> nodeExists = currentNode.FindChildNode(ch);
if (nodeExists != null)
{
// follow the if it exists, has a value
// and we are not on the last character
if (nodeExists.Value != null && (i != (key.Length - 1)))
{
currentNode = nodeExists;
break;
}
// if the node exists and we are on the last character
// update the value
else if (i == (key.Length - 1))
{
nodeExists.Value = value;
break;
}
else
{
// otherwise, continue down the path
currentNode = nodeExists;
break;
}
}
// create the character
else
{
tmpNode = new TrieNodeArray <ValueType>()
{
Character = ch, Parent = currentNode
};
// we are at the end of the key, save the value
if (i == (key.Length - 1))
{
currentNode.AddToChildren(tmpNode, value);
break;
}
else
{
currentNode.AddToChildren(tmpNode);
currentNode = currentNode.FindChildNode(ch);
break;
}
}
}
}
}
// removes node holding value
public void Remove()
{
Character = default(char);
Value = default(ValueType);
Parent = null;
}
