I find it a bit odd how this tree representation as a parents array (which is, by the way, I think the most basic representation in any CS course), got so much traction on HN. I think this goes to show how far a good presentation can drive a trivial idea. On top of that, it just casually presents suboptimal procedures for a lot of essential operations, without diving into too much details about the impact of the suboptimality. Good PR I guess…