private static void BuildTree()
{
HuffmanTrees.Sort();
while (HuffmanTrees.Count > 1)
{
var parent = new HuffmanTree();
if (HuffmanTrees[0].Frequency > HuffmanTrees[1].Frequency)
{
HuffmanTrees.Sort();
}
var min = HuffmanTrees[0];
var secondMin = HuffmanTrees[1];
if (parent.LeftChild == null)
{
parent.LeftChild = min;
min.Parent = parent;
HuffmanTrees.Remove(min);
}
if (parent.RightChild == null)
{
parent.RightChild = secondMin;
secondMin.Parent = parent;
HuffmanTrees.Remove(secondMin);
}
parent.Frequency = min.Frequency + secondMin.Frequency;
HuffmanTrees.Insert(0, parent);
}
if (HuffmanTrees != null || HuffmanTrees[0].Parent == null)
{
Root = HuffmanTrees[0];
}
}
public static SortedSet <string> Encode(string input)
{
HuffmanTrees = input
.GroupBy(c => c)
.Select(o => new HuffmanTree(o.Key, o.Count()))
.OrderBy(n => n.Frequency)
.ThenBy(n => n.Character).ToList();
Nodes = HuffmanTrees.ToArray <HuffmanTree>();
BuildTree();
Traverse(Root, 1);
var set = new SortedSet <string>();
foreach (var c in input)
{
var code = Array.Find(Nodes, n => n.Character == c).Binary;
set.Add(code);
}
return(set);
}
