How fool I was last night! I found my misunderstanding about the Problem C suddenly after coding more than 30 minutes and being failed to pass the sample. I re-analyse the sample and realized that what an idiot I was! Finally I solved the problem 10 min before the contest finished and got my rating decrease by 3 because of my high penalty. Reflecting on my failure , I think it's my urge to solve problems more quickly that accounts for it. I can't imagine what would be happened if I...I were to repeat it on the stage of ICPC. What I have to do is that form a good habit--always keeping calm and coding after well-thought. I hope that I can achieve it soon.

And I am looking forward to your comment about your own experience below my blog.