Given the re-submission penalty, in Codeforces Round 198 (Div. 2), I faced the loss of 50 points, thanks to a double request sent to the server in my only submission to problem A, which ultimately led to a difference of 281 places in terms of rank.
I'm not sure, whether if there's a solution to this problem or not. That's why I posted in here.
But I believe that there should be more precautions to avoid such a problem, as usually this is out of one's will to do that. Something like a confirm message such as that done at TopCoder, or comparing it with a previous submitted codes, such that one can't submit the same code more than once in the same Contest, or something like that.
The second option is there. You cannot submit the same code twice ..
My code (exact code) has been submitted twice, and the first was skipped, and I received 50 points less than those solving at the same time as I am.