After the big “dropping of ratings due to plagiarism” incident, it seems that Codechef cannot calculate the ratings of people accurately now. Why? Glad you asked. Here a few rating changes of people:
Rank Username Initial Rating New Rating Change
19 vaibhavvg 1546 1741 +195
159 sid_008 1546 1742 +196
21 notira 1500 1775 +275
130 reaper_mist 1500 1749 +249
So, firstly, if 2 people have the same initial rating, the person having a shittier rank in the contest gets a better final rating(1546==1546, 1741 < 1742, implies, rank 19 gets a lesser boost as compared to rank 159, given same initial rating).This means, I just wasted my time solving the 3rd problem and should’ve just let my rank slide to the bottom, because sid_008 solved just 2.
Secondly, @vijju123 was saying something about the codechef system being unique about its rating in a previous post. I also agree. Only on codechef can one perform worse and still get a better rating than his peers. Check out notira(rank 21). He had a rating of 1500 initially. After contest, he is now at 1775. I think we all can spot a basic logical error here.
Let there be 2 people A and B having ratings r1 and r2 respectively. Given r1 > r2 initially. A performs better than B in a contest. So, obviously A should have a better final rating than B (r1’ > r2’) . I agree that sometimes B can get a better boost(+ delta) than A here. But the final rating of B should never exceed A’s here.
This is precisely what has happened here. Rank 21, rank 130 and many more.
So one way I see is for codechef to rectify the error here, or correct me if I’m wrong in saying that a newer account should always be the alternative when your rating decreases.