public T pop()
{
if (root == null)
{
return(default(T));
}
Queue <HeapNode <T> > q = new Queue <HeapNode <T> >();
HeapNode <T> curr = root;
HeapNode <T> prev = null;
while (curr != null)
{
HeapNode <T> l = curr.getLeft();
q.Enqueue(l);
HeapNode <T> r = curr.getRight();
q.Enqueue(r);
prev = curr;
curr = q.Dequeue();
}
//case where root is the only one
//handle it here to avoid null pointers below
if (prev.Equals(root))
{
root = null;
return(prev.getNode());
}
//set last element in tree to root node
//set roots left and right to new root left and right
prev.setLeft(root.getLeft());
prev.setRight(root.getRight());
//set new root parents to this
if (prev.getLeft() != null)
{
prev.getLeft().setParent(prev);
}
if (prev.getRight() != null)
{
prev.getRight().setParent(prev);
}
//set prev's old parent's left or right branch to null
if (prev.getParent().getLeft().Equals(prev))
{
prev.getParent().setLeft(null);
}
else if (prev.getParent().getRight().Equals(prev))
{
prev.getParent().setRight(null);
}
//set prev parent to null since it will be the root
prev.setParent(null);
HeapNode <T> popVal = root;
root = prev;
//place prev in its correct place
//root.sort();
root = root.sortChild();
//completely disconnect popped value from tree
popVal.setParent(null);
popVal.setLeft(null);
popVal.setRight(null);
return(popVal.getNode());
}