private static void Sort_Nodes(HuffmanNode node, List <HuffmanNode> nodes)
{
if (nodes.Contains(node) == false)
{
nodes.Add(node);
}
if (node.Left != null)
{
Sort_Nodes(node.Left, nodes);
}
if (node.Right != null)
{
Sort_Nodes(node.Right, nodes);
}
}