Ejemplo n.º 1
0
        private void RotateRight(RedBLackNode <TKey, TValue> node)
        {
            var current = node.Left;

            node.Left = current.Right;

            if (!current.Right.IsLeaf)
            {
                current.Right.Parent = node;
            }

            current.Parent = node.Parent;

            if (node.Parent.IsLeaf)
            {
                _root = current;
            }
            else
            {
                if (node == node.Parent.Right)
                {
                    node.Parent.Right = current;
                }
                else
                {
                    node.Parent.Left = current;
                }
            }

            current.Right = node;
            node.Parent   = current;
        }
Ejemplo n.º 2
0
        private void BalanceAfterAddition(RedBLackNode <TKey, TValue> node)
        {
            while (node.Parent.Color == NodeColor.Red)
            {
                if (node.Parent == node.Parent.Parent.Left)
                {
                    var uncle = node.Parent.Parent.Right;

                    if (uncle.Color == NodeColor.Red)
                    {
                        node.Parent.Color        = NodeColor.Black;
                        uncle.Color              = NodeColor.Black;
                        node.Parent.Parent.Color = NodeColor.Red;
                        node = node.Parent.Parent;
                    }
                    else
                    {
                        if (node == node.Parent.Right)
                        {
                            node = node.Parent;
                            RotateLeft(node);
                        }

                        node.Parent.Color        = NodeColor.Black;
                        node.Parent.Parent.Color = NodeColor.Red;
                        RotateRight(node.Parent.Parent);
                    }
                }
                else
                {
                    var uncle = node.Parent.Parent.Left;

                    if (uncle.Color == NodeColor.Red)
                    {
                        node.Parent.Color        = NodeColor.Black;
                        uncle.Color              = NodeColor.Black;
                        node.Parent.Parent.Color = NodeColor.Red;
                        node = node.Parent.Parent;
                    }
                    else
                    {
                        if (node == node.Parent.Left)
                        {
                            node = node.Parent;
                            RotateRight(node);
                        }

                        node.Parent.Color        = NodeColor.Black;
                        node.Parent.Parent.Color = NodeColor.Red;
                        RotateLeft(node.Parent.Parent);
                    }
                }
            }

            _root.Color = NodeColor.Black;
        }
Ejemplo n.º 3
0
        private List <KeyValuePair <TKey, TValue> > Traverse(RedBLackNode <TKey, TValue> node)
        {
            var nodes = new List <KeyValuePair <TKey, TValue> >();

            if (!node.IsLeaf)
            {
                nodes.AddRange(Traverse(node.Left));
                nodes.Add(new KeyValuePair <TKey, TValue>(node.Key, node.Value));
                nodes.AddRange(Traverse(node.Right));
            }

            return(nodes);
        }
Ejemplo n.º 4
0
        public void Add(TKey key, TValue value)
        {
            var node    = new RedBLackNode <TKey, TValue>(key, value);
            var parent  = new RedBLackNode <TKey, TValue>();
            var current = _root;

            while (!current.IsLeaf)
            {
                parent = current;

                if (node.Key.CompareTo(current.Key) < 0)
                {
                    current = current.Left;
                }
                else if (node.Key.CompareTo(current.Key) > 0)
                {
                    current = current.Right;
                }
                else
                {
                    throw new ArgumentException("Item with same key has already been added");
                }
            }

            node.Parent = parent;

            if (parent.IsLeaf)
            {
                _root = node;
            }
            else if (node.Key.CompareTo(parent.Key) < 0)
            {
                parent.Left = node;
            }
            else
            {
                parent.Right = node;
            }

            node.Left  = new RedBLackNode <TKey, TValue>();
            node.Right = new RedBLackNode <TKey, TValue>();
            node.Color = NodeColor.Red;
            Count++;

            BalanceAfterAddition(node);
        }
Ejemplo n.º 5
0
 private RedBLackNode <TKey, TValue> Find(TKey key, RedBLackNode <TKey, TValue> node)
 {
     if (node.IsLeaf || key.CompareTo(node.Key) == 0)
     {
         return(node);
     }
     else
     {
         if (key.CompareTo(node.Key) < 0)
         {
             return(Find(key, node.Left));
         }
         else
         {
             return(Find(key, node.Right));
         }
     }
 }
Ejemplo n.º 6
0
        private RedBLackNode <TKey, TValue> Successor(RedBLackNode <TKey, TValue> node)
        {
            if (!node.Right.IsLeaf)
            {
                node = node.Right;

                while (!node.Left.IsLeaf)
                {
                    node = node.Left;
                }

                return(node);
            }

            var parent = node.Parent;

            while (!parent.IsLeaf && node == parent.Right)
            {
                node   = parent;
                parent = parent.Parent;
            }

            return(parent);
        }
Ejemplo n.º 7
0
 public RedBlackTree()
 {
     _root = new RedBLackNode <TKey, TValue>();
     Count = 0;
 }
Ejemplo n.º 8
0
 public void Clear()
 {
     _root = new RedBLackNode <TKey, TValue>();
     Count = 0;
 }
Ejemplo n.º 9
0
        private void BalanceAfterRemoving(RedBLackNode <TKey, TValue> node)
        {
            while (node != _root && node.Color == NodeColor.Black)
            {
                if (node == node.Parent.Left)
                {
                    var current = node.Parent.Right;

                    if (current.Color == NodeColor.Red)
                    {
                        current.Color     = NodeColor.Black;
                        node.Parent.Color = NodeColor.Red;
                        RotateLeft(node.Parent);
                        current = node.Parent.Right;
                    }

                    if (current.Left.Color == NodeColor.Black && current.Right.Color == NodeColor.Black)
                    {
                        current.Color = NodeColor.Red;
                        node          = node.Parent;
                    }
                    else
                    {
                        if (current.Right.Color == NodeColor.Black)
                        {
                            current.Left.Color = NodeColor.Black;
                            current.Color      = NodeColor.Red;
                            RotateRight(current);
                            current = node.Parent.Right;
                        }

                        current.Color       = node.Parent.Color;
                        node.Parent.Color   = NodeColor.Black;
                        current.Right.Color = NodeColor.Black;
                        RotateLeft(node.Parent);
                        node = _root;
                    }
                }
                else
                {
                    var current = node.Parent.Left;

                    if (current.Color == NodeColor.Red)
                    {
                        current.Color     = NodeColor.Black;
                        node.Parent.Color = NodeColor.Red;
                        RotateRight(node.Parent);
                        current = node.Parent.Left;
                    }

                    if (current.Left.Color == NodeColor.Black && current.Right.Color == NodeColor.Black)
                    {
                        current.Color = NodeColor.Red;
                        node          = node.Parent;
                    }
                    else
                    {
                        if (current.Left.Color == NodeColor.Black)
                        {
                            current.Right.Color = NodeColor.Black;
                            current.Color       = NodeColor.Red;
                            RotateLeft(current);
                            current = node.Parent.Left;
                        }

                        current.Color      = node.Parent.Color;
                        node.Parent.Color  = NodeColor.Black;
                        current.Left.Color = NodeColor.Black;
                        RotateRight(node.Parent);
                        node = _root;
                    }
                }
            }

            node.Color = NodeColor.Black;
        }
Ejemplo n.º 10
0
        public bool Remove(TKey key)
        {
            var node = Find(key, _root);

            if (node.IsLeaf)
            {
                return(false);
            }

            Count--;

            RedBLackNode <TKey, TValue> linkedNode;
            RedBLackNode <TKey, TValue> workNode;

            if (node.Left.IsLeaf || node.Right.IsLeaf)
            {
                workNode = node;
            }
            else
            {
                workNode = Successor(node);
            }

            if (!workNode.Left.IsLeaf)
            {
                linkedNode = workNode.Left;
            }
            else
            {
                linkedNode = workNode.Right;
            }

            linkedNode.Parent = workNode.Parent;

            if (workNode.Parent.IsLeaf)
            {
                _root = linkedNode;
            }
            else
            {
                if (workNode == workNode.Parent.Left)
                {
                    workNode.Parent.Left = linkedNode;
                }
                else
                {
                    workNode.Parent.Right = linkedNode;
                }
            }

            if (workNode != node)
            {
                node.Key   = workNode.Key;
                node.Value = workNode.Value;
            }

            if (workNode.Color == NodeColor.Black)
            {
                BalanceAfterRemoving(linkedNode);
            }

            return(true);
        }