Thanks for the nice script !
The example should just illustrate the problem. The strings in the list can be completely different and your solution will only work with this specific example.
There even might exists a better solution (with a lower score ($len)) for this example as the given one. I am looking for an idea how to come to a good and fast solution, accepting that this solution is not the best one, which can be found. (See also the answer of Bill)