BrowserUk,
I respect you greatly and I consider you a likable person so I apologize for trying your patience. I am not sure why I can't let this go - probably for the same reason I can't let go these interesting distractions. Please keep that in mind as I try and explain my actions - that I am just venting and would be happy to let this drop.

I did. Both via /msg, and repeatedly in this thread.

Yes, but you also kept responding even after I said don't feel obliged to indulge me. I misinterpreted this as "I might be interested but you haven't convinced me yet". My apologies.

So what value has the heuristic solution?

I too explained my reason, in this thread and through /msg. I learned things I didn't previously know. Techniques that may prove to be useful in the future. I discovered things that didn't work - which by itself is a useful lesson.

Had you once in your replies offline or on, indicated that you accepted the need for a reasonable performance brute force mechanism

I mentioned several times in this thread and via /msg that I was also working on a solution that provided a guaranteed optimal solution in a reasonable run time. You didn't inquire further. I agree that I didn't accept that it was necessary. I explained that the heuristic solutions would have personal intrinsic value to me even if I failed in the other task. I still don't think it is necessary but I recognize that if I wanted to gain your interest that is what it would have taken. My apologies and my loss.

With threading, that might be shortened further, and that's something that's right up my alley.

Well, I finally posted Challenge: Letter Power Revisited which requires solutions to be pure perl and run in roughly 60 seconds. I know you don't see any value in it but please do share anything you (C, threaded, etc). I would find value in it - I always learn from you.