Stefan Ram's solution:

Write time:
Several hours to an initial raw solution, then
some more hours for some trial-and-error sessions
to tune some parameters and to clean up the code.

Run time:
The program and my computer are both slow and so
it took dozens of hours to even find the submitted
solution, which is still far from the best solution.

I did it because I always wanted to write some
code using mutation and selection to find a solution.