I think your spidey sense serves you well.

This smells a little like homework, so I'm putting my solution in spoiler tags.

<Reveal this spoiler or all in this thread>

You should come up with your pairs, and for each pair keep a count (in a hash) of how many times that pair has been seen. Each key of the hash will be a pair, and each value will be the count of occurrences. Once you have that, you can sort the keys by the values and come up with the pair that appears the most. I suspect every one of these tasks has been the subject of some post you could find with Super Search.

In reply to Re: Finding Combinations of Pairs by kyle
in thread Finding Combinations of Pairs by zod

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