This deserves some discussion, but alas, I'm not a linear programming expert.

The article implies that the best solution was brute-force, and therefore they use Genetic Algorithms to search for a "pretty good" solution as opposed to the optimal solution.

Linear Programming on the other hand would find PRECISELY the optimal solution. But there are all kinds of constraints on what kinds of programs Linear Programming can solve.

It seems like this constraint problem can be solved through Linear Programming methods, but I'm not an expert in that algorithm. So maybe Jet.Com is being inefficient here with the algorithm (just a little bit inefficient).