Problem E: AC & WA.

Problem B: AC & WA. I forgot to put an else after the if, but I still don't know how it passed the samples.

Problem C: AC & WA. I forgot to check whether L > R. (Actually, I could've fixed this with a few small modifications to the code, but I didn't want to risk it because my brain cells were already cooked after Problem B.)

Also, since I was in an uncomfortable and noisy environment, I couldn't figure out how to solve problem D in time and solved problem A in 11 mins (as an Expert it's a shame)

In conclusion: Never, ever try to participate in a contest in an uncomfortable environment or You'll be cooked like me

Personal Thoughts: To be honest, I really enjoyed the problems, even though I ended up with a negative delta.

Thanks to the authors for organizing such a great contest: conqueror_of_tourist,TheOneYouWant,FlakeLCR,applepi216 orz