*A problem described can be related to Knapsack or The Travalling Salesman Problem--correctly described as NP-hard or NP-complete--but it can still be solved in real time using Perl when the CS majors give up. I've done this many times.*

The thing about NP complete problems is that *they don't scale*. It could be you can still find solutions for, for example, 20 nodes, while for just a few more nodes, solving the same problem takes many times longer, so long that it's no longer practically usable. Your particular problem may take a few minutes to solve, while the slighhtly more complex problem takes hours, or days.

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