/*
* Key insertion operation
* Complexity: O(n)
*/
public static BST <T> Insert(BST <T> _tree, T _value)
{
// Check if left or right child should be used
var comparison = _value.CompareTo(_tree.Value);
if (comparison < 0)
{
if (_tree.Left == null)
{
Console.WriteLine("Inserting {0} left of {1}",
_value, _tree.Value);
_tree.Left = new BST <T>(_value);
}
else
{
Console.WriteLine("Moving left of {0}",
_tree.Value);
_tree.Left = Insert(_tree.Left, _value);
}
}
else
{
if (_tree.Right == null)
{
Console.WriteLine("Inserting {0} right of {1}",
_value, _tree.Value);
_tree.Right = new BST <T>(_value);
}
else
{
Console.WriteLine("Moving right of {0}",
_tree.Value);
_tree.Right = Insert(_tree.Right, _value);
}
}
return(_tree);
}
/*
* Delete operation
* Complexity: O(n^2) because of the added cost of the successor-locating traversal
*/
public static BST <T> Delete(BST <T> _tree, T _value, BST <T> _root)
{
if (_tree == null)
{
Console.WriteLine("Value not found in tree");
}
else
{
var comparison = _value.CompareTo(_tree.Value);
if (comparison == 0)
{
if (_tree.Left == null && _tree.Right == null)
{
Console.WriteLine("Removing leaf {0}", _tree.Value);
_tree = null;
}
else if (_tree.Left != null && _tree.Right != null)
{
// Locate successor, copy and recursively delete
var traversal = TraverseInOrder(_root);
for (int i = 0; i < traversal.Count; i++)
{
if (_tree.Value.CompareTo(traversal[i].Value) == 0)
{
var successor = traversal[i + 1];
Console.WriteLine("Replacing {0} with successor {1}",
_tree.Value, successor.Value);
_tree.Value = successor.Value;
Console.WriteLine("Recursively calling delete on {0}",
_tree.Right.Value);
_tree.Right = Delete(_tree.Right, successor.Value, _root);
break;
}
}
}
else if (_tree.Left != null)
{
Console.WriteLine("Replacing {0} with right subtree {1}",
_tree.Value, _tree.Left.Value);
_tree = _tree.Left;
}
else
{
Console.WriteLine("Replacing {0} with right subtree {1}",
_tree.Value, _tree.Right.Value);
_tree = _tree.Right;
}
}
else if (comparison < 0)
{
Console.WriteLine("Moving left from {0}", _tree.Value);
_tree.Left = Delete(_tree.Left, _value, _root);
}
else
{
Console.WriteLine("Moving right from {0}", _tree.Value);
_tree.Right = Delete(_tree.Right, _value, _root);
}
}
return(_tree);
}
static bool Search <T>(BST <T> _tree, T _which) where T : IComparable
{
Console.WriteLine("Searching for {0}", _which.ToString());
return(BST <T> .Search(_tree, _which));
}