protected void PreOrderI()
{
// requires stack data structure
Node curr = getRoot();
if (curr == null)
{
return;
}
cStack s = new cStack();
s.push(curr);
while (!s.isEmpty())
{
curr = (Node)s.pop();
Console.Write("{0} ", curr.val);
if (curr.left != null)
{
s.push(curr.left);
}
if (curr.right != null)
{
s.push(curr.right);
}
}
}
protected void InOrderI()
{
/*
* this require Stack data structure. If you don't
* want to use stack you can check InOrderI2() which
* uses Morris tree traversal algorithm
*/
cStack stack = new cStack();
Node curr = getRoot();
while (1 == 1)
{
if (curr != null)
{
stack.push(curr);
curr = curr.left;
}
else
{
if (stack.isEmpty())
{
return;
}
else
{
curr = (Node)stack.pop();
Console.Write("{0} ", curr.val);
curr = curr.right;
}
} // curr!=null end
} // while end
}
protected void PostOrderI()
{
// requires stack data structure
Node curr = getRoot();
if (curr == null)
{
return;
}
cStack s = new cStack();
do
{
while (curr != null)
{
if (curr.right != null)
{
s.push(curr.right);
}
s.push(curr);
curr = curr.left;
}
curr = (Node)s.pop();
if (curr.right != null && (Node)s.peek() == curr.right)
{
s.pop();
s.push(curr);
curr = curr.right;
}
else
{
Console.Write("{0} ", curr.val);
curr = null;
}
} while(!s.isEmpty());
}
protected bool isBstI()
{
Node curr = getRoot();
if (curr == null)
{
return(false);
}
// if only root than it is bst
if (curr.right == null && curr.left == null)
{
return(true);
}
Node last = null;
cStack s = new cStack();
while (!s.isEmpty() && curr != null)
{
if (curr != null)
{
s.push(curr);
curr = curr.left;
}
else
{
curr = (Node)s.pop();
if (last != null && curr.val < last.val)
{
return(false);
}
last = curr;
curr = curr.right;
}
} // while end
return(true);
}