> I at least remembered how to depth first traverse it, but haven’t seen in order traversal since my freshman year of college. Well, to be fair an in-order tr

> I at least remembered how to depth first traverse it, but haven’t seen in order traversal since my freshman year of college. Well, to be fair an in-order traversal is not what you needed to solve that problem...an in-order traversal would get you the elements of the tree sorted, irrespective of level. This is not a "gotcha" problem where you either know it or you don't, it's about using a basic data structure in kind if a weird way.