public void Build(string source)
{
for (int i = 0; i < source.Length; i++)
{
if (!Frequencies.ContainsKey(source[i]))
{
Frequencies.Add(source[i], 0);
}
Frequencies[source[i]]++;
}
foreach (KeyValuePair<char, int> symbol in Frequencies)
{
nodes.Add(new Node() { Symbol = symbol.Key, Frequency = symbol.Value });
}
while (nodes.Count > 1)
{
List<Node> orderedNodes = nodes.OrderBy(node => node.Frequency).ToList<Node>();
if (orderedNodes.Count >= 2)
{
// Take first two items
List<Node> taken = orderedNodes.Take(2).ToList<Node>();
// Create a parent node by combining the frequencies
Node parent = new Node()
{
Symbol = '*',
Frequency = taken[0].Frequency + taken[1].Frequency,
Left = taken[0],
Right = taken[1]
};
nodes.Remove(taken[0]);
nodes.Remove(taken[1]);
nodes.Add(parent);
}
this.Root = nodes.FirstOrDefault();
}
}
public bool IsLeaf(Node node)
{
return (node.Left == null && node.Right == null);
}