/// <summary>
/// AVL rotate double-right operation.
/// </summary>
/// <param name="tree">The tree.</param>
/// <returns>The rotated tree.</returns>
private static SortedInt32KeyNode <TValue> DoubleRight(SortedInt32KeyNode <TValue> tree)
{
Requires.NotNull(tree, "tree");
Debug.Assert(!tree.IsEmpty);
if (tree._left.IsEmpty)
{
return(tree);
}
SortedInt32KeyNode <TValue> rotatedLeftChild = tree.Mutate(left: RotateLeft(tree._left));
return(RotateRight(rotatedLeftChild));
}
/// <summary>
/// AVL rotate right operation.
/// </summary>
/// <param name="tree">The tree.</param>
/// <returns>The rotated tree.</returns>
private static SortedInt32KeyNode <TValue> RotateRight(SortedInt32KeyNode <TValue> tree)
{
Requires.NotNull(tree, nameof(tree));
Debug.Assert(!tree.IsEmpty);
if (tree._left.IsEmpty)
{
return(tree);
}
var left = tree._left;
return(left.Mutate(right: tree.Mutate(left: left._right)));
}
/// <summary>
/// AVL rotate left operation.
/// </summary>
/// <param name="tree">The tree.</param>
/// <returns>The rotated tree.</returns>
private static SortedInt32KeyNode <TValue> RotateLeft(SortedInt32KeyNode <TValue> tree)
{
Requires.NotNull(tree, "tree");
Debug.Assert(!tree.IsEmpty);
if (tree._right.IsEmpty)
{
return(tree);
}
var right = tree._right;
return(right.Mutate(left: tree.Mutate(right: right._left)));
}