Thursday morning, I saw the problems and took a printout of the Flyswatter. Then I spent about 3 hours figuring out the right area calculations, without success.
Then I tried hacking away at the other 2 problems for a total of 1.75 hours. Again failed.
Result: A total brain burnout
Feeling: Really down for my not so leet algorithmic skills.
Lesson learned: I seriously need 4 years of formal computer science education.