public static HuffmanTree <T> BuildTree(List <HuffmanEntry <T> > items)
{
var nodes = items.Select(a => new HuffmanBinaryNode <T>()
{
Weight = a.Frequency,
Value = a.Value,
}).ToList();
SortNodes(nodes);
while (nodes.Count >= 2)
{
var nodeLeft = nodes[0];
var nodeRight = nodes[1];
nodes.RemoveAt(0);
nodes.RemoveAt(0);
var newNode = new HuffmanBinaryNode <T>()
{
LeftNode = nodeLeft,
RightNode = nodeRight,
Weight = nodeLeft.Weight + nodeRight.Weight
};
nodes.Add(newNode);
SortNodes(nodes);
}
return(new HuffmanTree <T>()
{
Root = nodes[0]
});
}
void Step(HuffmanBinaryNode <T> currentNode, List <HuffmanPath.Path> currentPath)
{
if (currentNode.LeftNode == null)
{
Table.Add(currentNode.Value, currentPath);
}
else
{
var leftList = new List <HuffmanPath.Path>(currentPath);
leftList.Add(HuffmanPath.Path.Left);
Step(currentNode.LeftNode, leftList);
var rightList = new List <HuffmanPath.Path>(currentPath);
rightList.Add(HuffmanPath.Path.Right);
Step(currentNode.RightNode, rightList);
}
}
