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Supposing you have a 3 or more overlapping arrays (arrays having elements in common), and you wish to select 2 or more of the arrays with the maximum number of elements but less overlap as compared to the rest of the overlapping arrays.

Eg. A[4],B[6],C[5]. A+B contains 10 elements but say the overlapping element is 3, meaning it has 7 unique element. Also B+C=11 elements , but supposing it has 5 overlaps, it would mean it has only 6 unique elements. A+B+C=15. Supposing the overlaps are 11 then it means the unique elements are 4. Ect. So per the example, the best array options with most unique element would be A+B

Are the elements in these 'arrays' unique? In other words, at a conceptual level, are we really talking about sets, intersection, union, cardinality, ...?

Note that if you have 'n' sets, you have 2^n combinations of sets.

"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." -- Antoine de Saint-Exupery

Your example cannot exists. A+B+C cannot have 11 elements in common. Anyway, this is not a problem about programming. You have to remind few maths to solve this. Try to remind Sets and sometimes, combinations and permutations.

Eg. A[4],B[6],C[5]. A+B contains 10 elements but say the overlapping element is 3, meaning it has 7 unique element. Also B+C=11 elements , but supposing it has 5 overlaps, it would mean it has only 6 unique elements. A+B+C=15. Supposing the overlaps are 11 then it means the unique elements are 4. Ect. So per the example, the best array options with most unique element would be A+B

If I had to solve this problem statement, I would most probably use Venn Diagrams and a couple of simple linear equations. But what is your question?