private void Add(IList <elementType> key, resultType value, int keyPos)
{
int size = key.Count - keyPos;
if (size > 0)
{
//add the node needed if nessesary
if (!nodes.ContainsKey(key[0]))
{
DSTNode <elementType, resultType> next = new DSTNode <elementType, resultType>();
next.init();
nodes.Add(key[0], next);
}
nodes[key[0]].Add(key, value, keyPos++);
}
else
{
if (result == null)
{
result = new List <resultType>();
result.Add(value);
count++;
}
else
{
throw new ArgumentException("An element with the same key already exists in the DST.");
}
}
}
/// <summary>
/// Get the item at an index.
/// NOTE: this should be the only way to map a index to an item.
/// All operations that are index bound must call this. This insures that there is only one key to item mapping in place.
/// </summary>
/// <param name="index">The index.</param>
/// <param name="count">The count.</param>
/// <param name="key">The key.</param>
/// <param name="value">The value.</param>
/// <returns></returns>
private bool ItemAtIndex(int index, int count, ref LinkedList <elementType> key, out resultType value)
{
int c = count;
Dictionary <elementType, DSTNode <elementType, resultType> > .KeyCollection keyList = nodes.Keys;
List <elementType> sortedKeyList = new List <elementType>(keyList);
//keyList.CopyTo(sortedKeyList, 0);
sortedKeyList.Sort();
foreach (elementType keyItem in sortedKeyList)
{
DSTNode <elementType, resultType> n = nodes[keyItem];
if ((c + n.count) >= index)
{
if (count == index)
{
//found a node whose final child is the one.
if (result != null)
{
value = this.result[0];
return(true);
}
}
if (ItemAtIndex(index, c, ref key, out value))
{
key.AddFirst(keyItem);
return(true);
}
}
c += n.count;
}
value = default(resultType);
return(false);
}
public DST()
{
rootNode = new DSTNode <elementType, resultType>();
rootNode.init();
}