Set Intersection of SortedRanges

[Nicholas Wilson via Digitalmars-d-learn]

On Monday, 5 December 2016 at 22:10:34 UTC, Nordlöw wrote:
> On Monday, 5 December 2016 at 21:48:49 UTC, Nordlöw wrote:
>> Ahh, setops has intersection aswell:
>>
>> https://dlang.org/phobos/std_algorithm_setops.html#setIntersection
>>
>> I should have a guessed that.
>
> Ahh again, but current Phobos is currently not optimized for 
> the case when all inputs are SortedArrays. In that case a 
> double binary search algorithm as describe here
>
> http://cs.stackexchange.com/a/37124/25769
>
> might be faster.
>
> Has anybody already done this?

The double binary search linked only finds *one* element of the 
intersection.

It should be as simple as a linear find (over the range of 
ranges) that returns (i.e. caches to .front) if the elements 
intersect.