Rating problems and solutions

We all know and love (!) the leaderboard, but how about a different method?

One can solve a problem with a simple, naive method resulting in a short program and long runtime, or put in lots of explicit optimizations for more code and shorter runtime. (Or if you're really good, a short, fast program!)

I propose the line-second.

Take the number of lines in your program (eg, 42 lines) and the runtime (eg 0.096 seconds). Multiply these together to get a score of 4.032 line-seconds.

A smaller score is a shorter, faster program.

Similarly, (for a particular solver), a larger score is a "harder" problem.