[OT] n-way union

[Andrei Alexandrescu]

bearophile wrote:
> For 	Andrei: in my last post I have suggested to remove from the heap
> the references to the sub-ranges as soon they are exhausted. But lot
> of tests of mine have shown me that's often not the most efficient
> strategy: http://www.fantascienza.net/leonardo/ar/list_deletions.html
>  So better things are possible. The most refined strategy may be
> overkill, but some medium strategy may be OK.

I don't think that applies here. Unstable removal is O(1) and restoring 
the heap property is O(n) in theory and very close to O(1) in practice.

Andrei