public void Insert(int data)
{
if (root == null)
{
root = new TreeNode(data);
root.ParentID = null;
root.NodeID = AddInDB(root);
return;
}
TreeNode parent = FindParent(data);
if (data < parent.value)
{
parent.left = new TreeNode(data);
parent.left.ParentID = parent.NodeID;
parent.left.NodeID = AddInDB(parent.left);
return;
}
parent.right = new TreeNode(data);
parent.right.ParentID = parent.NodeID;
parent.right.NodeID = AddInDB(parent.right);
return;
}
public TreeNode(int i)
{
value = i;
left = null;
right = null;
}
public BinaryTree()
{
root = null;
}
private TreeNode RemoveRec(TreeNode root, TreeNode nodeToDelete, bool removedFromDB = false)
{
if (root == null)
{
return root;
}
if (nodeToDelete.value < root.value)
{
root.left = RemoveRec(root.left, nodeToDelete, removedFromDB);
}
if (nodeToDelete.value > root.value)
{
root.right = RemoveRec(root.right, nodeToDelete, removedFromDB);
}
if (nodeToDelete.value == root.value)
{
if (root.left == null && root.right == null)
{
if (!removedFromDB)
{
RemoveFromDB(root, true);
}
root = null;
return root;
}
else if (root.left == null)
{
if (!removedFromDB)
{
RemoveFromDB(root, true);
}
root.right.ParentID = root.ParentID;
root = root.right;
}
else if (root.right == null)
{
if (!removedFromDB)
{
RemoveFromDB(root, false);
}
root.left.ParentID = root.ParentID;
root = root.left;
}
else
{
TreeNode mostLeft = root.right;
while (mostLeft.left != null)
{
mostLeft = mostLeft.left;
}
if (!removedFromDB)
{
RemoveFromDB(root, true, mostLeft);
}
root.value = mostLeft.value;
root.NodeID = mostLeft.NodeID;
root.right = RemoveRec(root.right, mostLeft, true);
if(root.right != null)
{
root.right.ParentID = root.NodeID;
}
if (root.left != null)
{
root.left.ParentID = root.NodeID;
}
}
}
return root;
}
public void Remove(int data)
{
TreeNode nodeToDelete = new TreeNode(data);
root = RemoveRec(root, nodeToDelete);
}
private void UpdateIDs(TreeNodeContext db, bool needRightChild, TreeNode nodeToRemove, TreeNode mostLeft)
{
var firstChildOfRemovingNode = needRightChild ? db.TreeNodes.SingleOrDefault(node => node.ParentID == nodeToRemove.NodeID && node.value >= nodeToRemove.value)
: db.TreeNodes.SingleOrDefault(node => node.ParentID == nodeToRemove.NodeID && node.value < nodeToRemove.value);
var leftChild = needRightChild ? db.TreeNodes.SingleOrDefault(node => node.ParentID == nodeToRemove.NodeID && node.value < nodeToRemove.value) : null;
if (firstChildOfRemovingNode != null)
{
if(mostLeft != null)
{
var mostLeftInDB = db.TreeNodes.SingleOrDefault(node => node.NodeID == mostLeft.NodeID);
mostLeftInDB.ParentID = nodeToRemove.ParentID;
if (leftChild != null)
{
leftChild.ParentID = mostLeft.NodeID;
}
if(mostLeftInDB.NodeID == firstChildOfRemovingNode.NodeID)
{
db.SaveChanges();
return;
}
firstChildOfRemovingNode.ParentID = mostLeftInDB.NodeID;
db.SaveChanges();
return;
}
firstChildOfRemovingNode.ParentID = nodeToRemove.ParentID;
db.SaveChanges();
}
}
private void RemoveFromDB(TreeNode node, bool needRightChild, TreeNode mostLeft = null)
{
using (TreeNodeContext db = new TreeNodeContext())
{
UpdateIDs(db, needRightChild, node, mostLeft);
var nodeToRemove = db.TreeNodes.SingleOrDefault(n => n.NodeID == node.NodeID);
if (nodeToRemove != null)
{
db.TreeNodes.Remove(nodeToRemove);
}
db.SaveChanges();
}
}
private int AddInDB(TreeNode node)
{
using (TreeNodeContext db = new TreeNodeContext())
{
db.TreeNodes.Add(node);
db.SaveChanges();
return node.NodeID;
}
}
