I would put each element from each set into a Disjoin-set data structure [1] and then report back all the sets whose elements all have cardinality 1. The compl

I would put each element from each set into a Disjoin-set data structure [1] and then report back all the sets whose elements all have cardinality 1. The complexity of this data structure is pretty interesting. It basically comes to O(N) for N < any number that can be represented in the known universe. It's also the coolest use of the inverse ackermann function I've seen! How to solve this on a distributed system I have no idea. [1] https://en.wikipedia.org/wiki/Disjoint-set_data_structure https://en.wikipedia.org/wiki/Disjoint-set_data_structure