private void Add(BookBSTNode node, int isbn, Book book)
{
if (node.isbn < isbn)
{
// go right
if (node.right == null)
{
node.right = new BookBSTNode(isbn, book);
}
else
{
Add(node.right, isbn, book);
}
}
else if (node.isbn > isbn)
{
// go left
if (node.left == null)
{
node.left = new BookBSTNode(isbn, book);
}
else
{
Add(node.left, isbn, book);
}
}
else
{
// Same ISBN, not allowed
throw new Exception("Duplicate ISBNs are not allowed.");
}
}
private BookBSTNode FindMax(BookBSTNode node)
{
while (node.right != null)
{
node = node.right;
}
return(node);
}
private void Print(BookBSTNode node)
{
if (node == null)
{
return;
}
Print(node.left);
Console.WriteLine(node.book.Isbn);
Print(node.right);
}
private void GetBookList(BookBSTNode current, List <Book> books)
{
if (current == null)
{
return;
}
GetBookList(current.left, books);
books.Add(current.book);
GetBookList(current.right, books);
}
public Book Remove(int isbn)
{
Book book;
root = Remove(root, isbn, out book);
if (book != null)
{
return(book);
}
throw new Exception("The ISBN was not found in the BST");
}
public void Add(Book book)
{
if (root == null)
{
root = new BookBSTNode(book.Isbn, book);
}
else
{
Add(root, book.Isbn, book);
}
}
private void PrintSideways(BookBSTNode root, int level)
{
if (root != null)
{
PrintSideways(root.right, level + 1);
for (int i = 0; i < level; i++)
{
Console.Write(" ");
}
Console.WriteLine(root.isbn);
PrintSideways(root.left, level + 1);
}
}
private BookBSTNode Remove(BookBSTNode root, int isbn, out Book returnBook)
{
// Used to pass the book to an output parameter
returnBook = null;
if (root == null)
{
return(null);
}
if (isbn < root.isbn)
{
root.left = Remove(root.left, isbn, out returnBook);
}
else if (isbn > root.isbn)
{
root.right = Remove(root.right, isbn, out returnBook);
}
else
{
// found it, populate the output variable
returnBook = root.book;
// Case 1: No Child
if (root.IsLeaf())
{
root = null;
}
// Case 2: One child
else if (root.left == null)
{
root = root.right;
}
else if (root.right == null)
{
root = root.left;
}
// Case 3: Two children
else
{
Book removed; // unused output parameter
BookBSTNode maxBookBstNode = FindMax(root.left);
root.book = maxBookBstNode.book;
root.isbn = maxBookBstNode.isbn;
root.left = Remove(root.left, maxBookBstNode.isbn, out removed);
}
}
return(root);
}
private Book Find(BookBSTNode node, int isbn)
{
if (node == null)
{
throw new Exception("ISBN #" + isbn + " was not found");
}
if (node.isbn == isbn)
{
// Exit condition
return(node.book);
}
// There's a value != to isbn
if (isbn < node.isbn)
{
return(Find(node.left, isbn));
}
// Go right
return(Find(node.right, isbn));
}
