Exemplo n.º 1
0
        private BinaryTreeNode <T> FindNodeAndParent(T value, BinaryTreeNode <T> current, ref BinaryTreeNode <T> parent)
        {
            var comparison = value.CompareTo(current.Value);

            while (comparison != 0)
            {
                if (comparison > 0) // value is bigger than current node search right subtree
                {
                    parent  = current;
                    current = current.RightChild;
                }
                else if (comparison < 0) // value is smaller than current node search left subtree
                {
                    parent  = current;
                    current = current.LeftChild;
                }

                if (current is null)
                {
                    return(current);
                }
                else
                {
                    comparison = value.CompareTo(current.Value);
                }
            }

            return(current);
        }
Exemplo n.º 2
0
 public BinarySearchTree(BinaryTreeNode <T> root) : base(root)
 {
 }
Exemplo n.º 3
0
        public void DeleteByValue(T value)
        {
            BinaryTreeNode <T> parent = null;

            var toRemove = FindNodeAndParent(value, Root, ref parent);

            var position = toRemove.CompareTo(parent);

            // Case 1: if toRemove has no right child replace with leftChild
            if (toRemove.RightChild is null)
            {
                if (position < 0)
                {
                    parent.LeftChild = toRemove.LeftChild; // replace parent left child with left child of the node you want to remove;
                }
                else if (position > 0)
                {
                    parent.RightChild = toRemove.LeftChild; // replace parent right child with left child of the node you want to remove;
                }
                else
                {
                    throw new Exception("Current node is the same as its parent... You've got a bug! (or a single node tree)");
                }
            }

            // Case 2: if toRemove right child has no left child replace with rightChild
            else if (toRemove.RightChild.LeftChild is null)
            {
                if (position < 0)
                {
                    parent.LeftChild           = toRemove.RightChild; // replace parent right child with left child of the node you want to remove;
                    parent.LeftChild.LeftChild = toRemove.LeftChild ?? null;
                }
                else if (position > 0)
                {
                    parent.RightChild           = toRemove.RightChild; // replace parent right child with right child of the node you want to remove;
                    parent.RightChild.LeftChild = toRemove.LeftChild ?? null;
                }
                else
                {
                    throw new Exception("Current node is the same as its parent... You've got a bug! (or a single node tree)");
                }
            }

            // Case 3: if toRemove right child has left child replace with toRemove.rightChild's leftmost descendant
            else if (toRemove.RightChild.LeftChild != null)
            {
                if (position < 0)
                {
                    parent.LeftChild            = FindLeftmostDescendant(toRemove.RightChild);
                    parent.LeftChild.LeftChild  = toRemove.LeftChild ?? null;
                    parent.LeftChild.RightChild = toRemove.RightChild ?? null;
                }
                else if (position > 0)
                {
                    var replacement = FindLeftmostDescendant(toRemove.RightChild);
                    FindParentNode(replacement).RemoveLeftChild();
                    parent.RightChild            = replacement;
                    parent.RightChild.LeftChild  = toRemove.LeftChild ?? null;
                    parent.RightChild.RightChild = toRemove.RightChild ?? null;
                }
                else
                {
                    throw new Exception("Current node is the same as its parent... You've got a bug! (or a single node tree)");
                }
            }

            _nodes.Remove(toRemove);
        }