public Tuple <IImmutableTree <TKey, TValue>, bool, TValue> TryRemove(TKey key)
{
IImmutableTree <TKey, TValue> result;
var comparison = _comparer.Compare(key, _key);
bool removed;
TValue val;
if (0 == comparison)
{
removed = true;
val = _value;
if (Right.IsEmpty && Left.IsEmpty)
{
result = new ImmutableTreeAcorn <TKey, TValue>(_comparer, _keyCloner, _valueCloner);
}
else if (Right.IsEmpty && !Left.IsEmpty)
{
result = Left;
}
else if (!Right.IsEmpty && Left.IsEmpty)
{
result = Right;
}
else
{
var s = Right;
while (!s.Left.IsEmpty)
{
s = s.Left;
}
result = new ImmutableTree <TKey, TValue>(_comparer, _keyCloner, _valueCloner, s.RootKey, s.RootValue, Left,
Right.TryRemove(s.RootKey).Item1);
}
}
else if (comparison < 0)
{
var removal = Left.TryRemove(key);
removed = removal.Item2;
val = removal.Item3;
result = new ImmutableTree <TKey, TValue>(_comparer, _keyCloner, _valueCloner, _key, _value, removal.Item1,
Right);
}
else
{
var removal = Right.TryRemove(key);
removed = removal.Item2;
val = removal.Item3;
result = new ImmutableTree <TKey, TValue>(_comparer, _keyCloner, _valueCloner, _key, _value, Left,
removal.Item1);
}
var br = BalanceTree(result);
return(Tuple.Create(br, removed, val));
}
private IImmutableTree <TKey, TValue> RotateRightRight(IImmutableTree <TKey, TValue> tree)
{
if (tree.Left.IsEmpty)
{
return(tree);
}
var rotatedLeftChild = new ImmutableTree <TKey, TValue>(_comparer, _keyCloner, _valueCloner, tree.RootKey,
tree.RootValue, RotateLeft(tree.Left), tree.Right);
return(RotateRight(rotatedLeftChild));
}
public IImmutableTree <TKey, TValue> Add(TKey key, TValue value)
{
var comparison = _comparer.Compare(key, _key);
if (0 == comparison)
{
return(new ImmutableTree <TKey, TValue>(_comparer, _keyCloner, _valueCloner, key, value, Left, Right));
}
ImmutableTree <TKey, TValue> result = comparison > 0
? new ImmutableTree <TKey, TValue>(_comparer, _keyCloner, _valueCloner, _key,
_value, Left, Right.Add(key, value))
: new ImmutableTree <TKey, TValue>(_comparer, _keyCloner, _valueCloner, _key,
_value, Left.Add(key, value), Right);
return(BalanceTree(result));
}
public IImmutableTree <TKey, TValue> AddOrUpdate(TKey key, TValue value, Func <TKey, TValue, TValue> updateValueFactory)
{
ImmutableTree <TKey, TValue> result;
var comparison = _comparer.Compare(key, _key);
if (comparison > 0)
{
result = new ImmutableTree <TKey, TValue>(_comparer, _keyCloner, _valueCloner, _key, _value, Left,
Right.AddOrUpdate(key, value, updateValueFactory));
}
else if (comparison < 0)
{
result = new ImmutableTree <TKey, TValue>(_comparer, _keyCloner, _valueCloner, _key, _value,
Left.AddOrUpdate(key, value, updateValueFactory), Right);
}
else
{
result = new ImmutableTree <TKey, TValue>(_comparer, _keyCloner, _valueCloner, key,
updateValueFactory(key, _value), Left, Right);
}
return(BalanceTree(result));
}
