public ArrayList<Object> toArrayList(ArrayList<Object> list) {
if (left == null && right == null) {
list.add(this);
return list;
}
list.add(this);
if (left != null) {
left.toArrayList(list);
}
if (right != null) {
right.toArrayList(list);
}
return list;
}
public ArrayList<Object> toArrayList() {
ArrayList<Object> list = new ArrayList<Object>();
if (root == null) {
return list;
}
return root.toArrayList(list);
}