/// <summary>
/// Adds an element with the specified key and value into the <see cref="BinarySearchTreeMap{TKey, TValue}"/>.
/// </summary>
/// <param name="key">The key of the element to add.</param>
/// <param name="value">The value of the element to add.</param>
public virtual void Add(TKey key, TValue value)
{
if (Root == null)
{
Root = new BinarySearchTreeMapNode <TKey, TValue>(key, value);
Count++;
return;
}
var curNode = Root;
var lastNode = Root;
bool addedToLeftSide = true;
while (curNode != null)
{
int cmp = comparer.Compare(key, curNode.Key);
if (cmp < 0)
{
lastNode = curNode;
curNode = curNode.Left;
addedToLeftSide = true;
}
else if (cmp > 0)
{
lastNode = curNode;
curNode = curNode.Right;
addedToLeftSide = false;
}
else
{
throw new ArgumentException("Tried to insert duplicate key!");
}
}
if (addedToLeftSide)
{
lastNode.Left = new BinarySearchTreeMapNode <TKey, TValue>(key, value);
Count++;
}
else
{
lastNode.Right = new BinarySearchTreeMapNode <TKey, TValue>(key, value);
Count++;
}
}
/// <summary>
/// Determines whether an element with the specified value is contained in the <see cref="BinarySearchTreeMap{TKey, TValue}"/>.
/// </summary>
/// <param name="value">The value to check.</param>
/// <returns>true if value is found; otherwise false.</returns>
public virtual bool ContainsValue(TValue value)
{
if (Root == null)
{
return(false);
}
HashSet <BinarySearchTreeMapNode <TKey, TValue> > cleared = new HashSet <BinarySearchTreeMapNode <TKey, TValue> >();
Stack <BinarySearchTreeMapNode <TKey, TValue> > stack = new Stack <BinarySearchTreeMapNode <TKey, TValue> >();
stack.Push(Root);
while (stack.Count > 0)
{
BinarySearchTreeMapNode <TKey, TValue> curNode = stack.Peek();
if (curNode.Left == null || cleared.Contains(curNode.Left))
{
cleared.Add(curNode);
stack.Pop();
if (object.Equals(value, curNode.Value))
{
return(true);
}
if (curNode.Right != null)
{
stack.Push(curNode.Right);
}
}
else
{
stack.Push(curNode.Left);
}
}
return(false);
}
/// <summary>
/// Gets or sets the value associated with the specified key in the <see cref="BinarySearchTreeMap{TKey, TValue}"/>.
/// </summary>
/// <param name="key">The key of the value to get or set.</param>
/// <returns>The value associated with the specified key. If the specified key is not found,
/// the get operation throws a <see cref="KeyNotFoundException"/>, and
/// the set operation creates a new element with the specified key.</returns>
public virtual TValue this[TKey key]
{
get
{
TValue value;
if (TryGetValue(key, out value))
{
return(value);
}
else
{
throw new KeyNotFoundException();
}
}
set
{
if (Root == null)
{
Root = new BinarySearchTreeMapNode <TKey, TValue>(key, value);
Count++;
return;
}
var curNode = Root;
var lastNode = Root;
bool addedToLeftSide = true;
while (curNode != null)
{
int cmp = comparer.Compare(key, curNode.Key);
if (cmp < 0)
{
lastNode = curNode;
curNode = curNode.Left;
addedToLeftSide = true;
}
else if (cmp > 0)
{
lastNode = curNode;
curNode = curNode.Right;
addedToLeftSide = false;
}
else // found the key
{
curNode.Value = value;
return;
}
}
if (addedToLeftSide)
{
lastNode.Left = new BinarySearchTreeMapNode <TKey, TValue>(key, value);
Count++;
}
else
{
lastNode.Right = new BinarySearchTreeMapNode <TKey, TValue>(key, value);
Count++;
}
}
}
/// <summary>
/// Finds the min node in the subtree and returns the root of the new subtree
/// </summary>
private BinarySearchTreeMapNode <TKey, TValue> FindAndRemoveMin(BinarySearchTreeMapNode <TKey, TValue> subtreeRoot, ref BinarySearchTreeMapNode <TKey, TValue> min)
{
if (subtreeRoot.Left == null)
{
if (subtreeRoot.Right == null)
{
min = subtreeRoot;
return(null);
}
else
{
min = subtreeRoot;
return(subtreeRoot.Right);
}
}
var curNode = subtreeRoot;
var lastNode = subtreeRoot;
while (curNode.Left != null)
{
lastNode = curNode;
curNode = curNode.Left;
}
lastNode.Left = curNode.Right;
min = curNode;
return(subtreeRoot);
}
/// <summary>
/// Removes an element with the specified key from the <see cref="BinarySearchTreeMap{TKey, TValue}"/>.
/// </summary>
/// <param name="key">The key of the element to remove.</param>
/// <returns>true if the element is successfully removed; otherwise false. Also returns false if element is not found.</returns>
public virtual bool Remove(TKey key)
{
if (Root == null)
{
return(false);
}
var curNode = Root;
var lastNode = Root;
bool lastWasLeftSide = true;
while (curNode != null)
{
int cmp = comparer.Compare(key, curNode.Key);
if (cmp < 0)
{
lastNode = curNode;
curNode = curNode.Left;
lastWasLeftSide = true;
}
else if (cmp > 0)
{
lastNode = curNode;
curNode = curNode.Right;
lastWasLeftSide = false;
}
else
{
if (curNode.Right == null)
{
if (lastWasLeftSide)
{
if (curNode == Root)
{
Root = curNode.Left;
}
else
{
lastNode.Left = curNode.Left;
}
}
else
{
lastNode.Right = curNode.Left;
}
}
else
{
BinarySearchTreeMapNode <TKey, TValue> min = null;
var rightNode = FindAndRemoveMin(curNode.Right, ref min);
min.Right = rightNode;
min.Left = curNode.Left;
if (lastWasLeftSide)
{
if (curNode == Root)
{
Root = min;
}
else
{
lastNode.Left = min;
}
}
else
{
lastNode.Right = min;
}
}
curNode.Invalidate();
Count--;
return(true);
}
}
return(false);
}
