/// <summary>
/// Merges two huffman tree nodes and creates a new non-leaf node which quantity
/// is equal to sum of quantities of given nodes.
/// </summary>
/// <param name="first">first node to merge</param>
/// <param name="second">second node to merge</param>
/// <returns>a node representing a parent of given nodes</returns>
private HuffmanTreeNode <T> Merge(HuffmanTreeNode <T> left, HuffmanTreeNode <T> right)
{
var parent = new HuffmanTreeNode <T>(
value: left.Value,
quantity: left.Quantity + right.Quantity,
subTreeDepth: Math.Max(left.SubTreeDepth, right.SubTreeDepth) + 1
)
{
LeftChild = left,
RightChild = right
};
left.Parent = right.Parent = parent;
return(parent);
}
public int Compare(HuffmanTreeNode <T> x, HuffmanTreeNode <T> y)
{
if (x.Quantity != y.Quantity)
{
return(x.Quantity - y.Quantity);
}
if (x.SubTreeDepth != y.SubTreeDepth)
{
return(x.SubTreeDepth - y.SubTreeDepth);
}
var valueComparerResult = valueComparer.Compare(x.Value, y.Value);
if (valueComparerResult == 0)
{
throw new Exception("Two huffman nodes cannot be equal to each other");
}
return(valueComparerResult);
}