Challenge #25: Creating Merchant Combos

[agulati]

Follow simple logic: the combinations should not repeat. We are calculating combinations and not permutations. For each user ID, the distinct combinations are NC2 (combinations of 2). Note: consider NULL also as one entity.

I have provided the most fundamental solution for this problem.

[Medha31]

PFA my solution

[DQAUDIT]

Solution attached.

[Matthew]

Solution

[Carolyn]

Solved! The hardest part was keeping the null <-> non-null combos to get the same number of results as the solution has :) 

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[AndrewDMerrill]

Simple problem that broke my brain because I struggle to read sometimes, apparently... :)

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[ds_tomalexsmith]

Spoiler

 

[RasmusFormo]

Spoiler

[Rob-Silk]

My solution below, probably not the most elegant or dynamic approach:

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[Amy_smart]

Here is my solution.