コード例 #1
0
        public override void remove(T val)
        {
            AVLTreeNode <T> parent;
            AVLTreeNode <T> current = searchWithParent(val, out parent);

            if (current == null)
            {
                return;
            }


            //Удаление листа
            if (current.left == null && current.right == null)
            {
                if (parent.left == current)
                {
                    parent.left = null;
                }
                else
                {
                    parent.right = null;
                }
                rebalance(parent);
                return;
            }

            //Удаляемый элемент имеет одного потомка
            if (current.left == null || current.right == null)
            {
                if (current.left == null)
                {
                    if (parent == null)
                    {
                        root = current.right;
                    }
                    else
                    {
                        if (parent.left == current)
                        {
                            parent.left = current.right;
                        }
                        else
                        {
                            parent.right = current.right;
                        }
                    }
                }
                else
                {
                    if (parent == null)
                    {
                        root = current.left;
                    }
                    else
                    {
                        if (parent.left == current)
                        {
                            parent.left = current.left;
                        }
                        else
                        {
                            parent.right = current.left;
                        }
                    }
                }
                rebalance(parent);
                return;
            }

            //Удаляемый элемент имеет двух потомков
            if (current.left != null && current.right != null)
            {
                AVLTreeNode <T> binaryTreeNode       = current.left;
                AVLTreeNode <T> parentBinaryTreeNode = current;
                while (binaryTreeNode.right != null)
                {
                    parentBinaryTreeNode = binaryTreeNode;
                    binaryTreeNode       = binaryTreeNode.right;
                }

                binaryTreeNode.right = current.right;

                if (parentBinaryTreeNode != current)
                {
                    parentBinaryTreeNode.right = binaryTreeNode.left;
                    binaryTreeNode.left        = current.left == binaryTreeNode ? null : current.left;
                }

                if (parent == null)
                {
                    root = binaryTreeNode;
                }
                else
                {
                    if (parent.left == current)
                    {
                        parent.left = binaryTreeNode;
                    }
                    else
                    {
                        parent.right = binaryTreeNode;
                    }
                }
                rebalance(binaryTreeNode);
            }
        }