In the recent Codeforces Round 1098 (Div. 2), I started solving the problems in a different order. I started with C1, then went on to B and A respectively, and then came back to C2, which was really just a small change compared to C1.

When submitting C2, I accidentally selected C1, which, of course, being the same problem just easier, got accepted.

After the contest, I saw my first accepted submission of C1 (at around 1:00 into the contest) got skipped, while the second (and last) accepted submission of C1 (at around 1:35) got accepted. After a web search, I found out that system testing takes into consideration only the last accepted submission of a problem. This led to me losing about 500 points and dropping (probably, I haven’t counted) a few hundred places.

Why? Just why? Why does it matter if I had 2 submissions of the same problem? It doesn’t make any sense from my perspective, and I want to hear your opinions on this. Thank you.