(sorry my English is poor.)
I have a question: if I submit once before, and past the pretests, and I submit a new code later, as the rule says, I will get -50 scores, but when I viewed the standing during the contest, my score of E1 changed from 944->802, and my rank fell nearly 100rks. Is this normal? Is this a bug or just a misunderstanding of the rules?
This is normal, the score is based on submission time
I think Codeforces considers your latest submission, in Div2s atleast, so its probably more time penalty.
Yes, I guess.
I have also resubmitted B2, thinking I'll just lose 50 points, but then I have found my first submission was skipped.
Yes,it's normal because of more penalty.