I dig this problem. One thing it doesn't touch, though, is the importance of using descriptive variable names to organize your thinking (in this case the var na

I dig this problem. One thing it doesn't touch, though, is the importance of using descriptive variable names to organize your thinking (in this case the var names are kind of a given--left, right, node..."current" is the only one someone might find a useless name for). I've found the candidate's ability to choose descriptive variable names is strongly correlated with general organization and clarity of their thinking.