public Node <int> searchRecursive(Node <int> root, int key)
{
//base case is root null or key found
if (root == null || root.getData().Equals(key))
{
return(root);
}
//if key less than root key, traverse left subtree
if (key < root.getData())
{
return(searchRecursive(root.getLeft(), key));
}
//if key greater than root key, traverse right subtree
return(searchRecursive(root.getRight(), key));
}
//first level, then second level, etc
public void breadthFirst()
{
Queue <Node <int> > queue = new Queue <Node <int> >();
if (root == null)
{
return;
}
queue.Enqueue(root);
//use a queue to list the nodes breadth first
while (queue.Count != 0)
{
Node <int> n = queue.Dequeue();
Console.Write(n.getData() + " ");
//if we have left node, add it to the end of the queue
if (n.getLeft() != null)
{
queue.Enqueue(n.getLeft());
}
//if we have right node, add it to the end of the queue
if (n.getRight() != null)
{
queue.Enqueue(n.getRight());
}
}
}
public Node <int> insertRecursive(Node <int> root, Node <int> parent, int key)
{
if (root == null)
{
return(new Node <int>(parent, key));
}
if (key < root.getData())
{
root.setLeft(insertRecursive(root.getLeft(), root, key));
}
else if (key > root.getData())
{
root.setRight(insertRecursive(root.getRight(), root, key));
}
return(root);
}
public Node <int> deleteRecursive(Node <int> root, int key)
{
if (root == null)
{
return(root);
}
//if key less than root key, traverse left subtree
if (key < root.getData())
{
root.setLeft(deleteRecursive(root.getLeft(), key));
}
//if key greater than root key, traverse right subtree
else if (key > root.getData())
{
root.setRight(deleteRecursive(root.getRight(), key));
}
//found node to delete
else
{
//node to delete has zero or one child node
if (root.getLeft() == null)
{
if (root.getRight() != null)
{
root.getRight().setParent(root.getParent());
}
return(root.getRight());
}
else if (root.getRight() == null)
{
if (root.getLeft() != null)
{
root.getLeft().setParent(root.getParent());
}
return(root.getLeft());
}
//node to delete has two children, so find the smallest node on the right subtree
//replace the node to delete with that node, then delete the smallest node on the right subtree
root.setData(getMinValue(root.getRight()));
root.setRight(deleteRecursive(root.getRight(), root.getData()));
}
return(root);
}
//get smallest key from a tree
public int getMinValue(Node <int> root)
{
int minValue = root.getData();
while (root.getLeft() != null)
{
minValue = root.getLeft().getData();
root = root.getLeft();
}
return(minValue);
}
public void printPostOrder(Node <int> root)
{
if (root == null)
{
return;
}
//traverse left subtree recursively
printPostOrder(root.getLeft());
//traverse right subtree recursively
printPostOrder(root.getRight());
//root node
Console.Write(root.getData() + " ");
}