I think parent’s construction works just fine if you disallow removes, so it grows monotonically, regardless of how dramatic the increase in keys, so long as yo

I think parent’s construction works just fine if you disallow removes, so it grows monotonically, regardless of how dramatic the increase in keys, so long as you move over 2 keys for every update to your map. My comment was a description of a precise “drastic change” where incrementality becomes sophisticated. (Though in part I was hoping for a response which identifies an elegant approach without the complication I mentioned.)