//Recursive method to build codes, starting at top node
public Dictionary <char, string> getEncodeMap(HuffmanNode top, string result)
{
if (top.Left != null)
{
getEncodeMap(top.Left, result + "0");
}
if (top.Right != null)
{
getEncodeMap(top.Right, result + "1");
}
//We've reached a leaf
if (top.Left == null)
{
if (!encodeData.ContainsKey(top.Symbol))
{
encodeData.Add(top.Symbol, result);
}
}
return(encodeData);
}
public void Build(Vector <char> vector)
{
//Get our frequencies
var dict = getFrequencyTable(vector).OrderBy(values => values.Value);
List <HuffmanNode> nodes = new List <HuffmanNode>();
//Build nodes based on those frequencies
foreach (KeyValuePair <char, int> nodeData in dict)
{
HuffmanNode node = new HuffmanNode();
node.Symbol = nodeData.Key;
node.Value = nodeData.Value;
nodes.Add(node);
}
while (nodes.Count > 1)
{
//Get lowest vals
HuffmanNode smallest = nodes[0];
HuffmanNode nextSmallest = nodes[1];
//Create parent
HuffmanNode parent = new HuffmanNode();
//Set value and children
parent.Value = smallest.Value + nextSmallest.Value;
parent.Left = smallest;
parent.Right = nextSmallest;
//Add parent to top of queue
nodes.Add(parent);
//Remove values from list
nodes.Remove(smallest);
nodes.Remove(nextSmallest);
//Reorder list to maintain integrity
nodes = nodes.OrderBy(values => values.Value).ToList();
}
Root = nodes[0]; //This is top of tree
}