public static HuffmanTree Build(Dictionary <string, int> Frequencies)
{
HuffmanTree tree = new HuffmanTree();
foreach (KeyValuePair <string, int> symbol in Frequencies)
{
tree.nodes.Add(new Node()
{
Symbol = symbol.Key, Frequency = symbol.Value
});
}
while (tree.nodes.Count > 1)
{
List <Node> orderedNodes = tree.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]
};
tree.nodes.Remove(taken[0]);
tree.nodes.Remove(taken[1]);
tree.nodes.Add(parent);
}
tree.Root = tree.nodes.FirstOrDefault();
}
return(tree);
}
