# ICPC online round tie-breaking ranking procedure

I see CodeChef just sums up the time taken to solve individual problems instead of taking the max time to solve all of the problems. Isn’t it odd? Even in competitions like Google KickStart etc and many other places only the latest correct submission time is taken for ranking.

Let me explain this with an example,
Suppose there are 3 questions in a contest,
Question 1 (Easy),
Question 2 (Medium),
Question 3 (Hard)

Suppose User 1 solves the problem 1 in 10th min, problem 2 in 25th min and problem 3 in 70th min with 1 penalty

Total time according to CodeChef ranking algorithm = 10 + 25 + 80 (+20 for penalty) = 125
As per the latest submission time, total time = 70 (+20 for penalty) = 90

And User 2 solves the problem 3 first in 30th min, problem 2 in 40th min with 1 penalty and problem 1 at the end in the 45th min.

Total time according to CodeChef ranking algorithm = 30 + 40 (+20 for penalty) + 45 = 135
As per the latest submission time, total time = 45 (+20 for penalty) = 65.

Clearly, CodeChef’s algorithm will rank User 1 higher(better) although User 2 has actually performed much better. Just because I opened the wrong problem first to solve say relatively difficult in comparison to the easiest question, does this make sense that being User 2, I would be ranked higher (i.e., worse in rank list). This hurts especially when there is a competition like ICPC.

4 Likes

There is nothing that CodeChef can really do. The same ranking system is followed in ICPC regionals and world finals, so it makes sense to use the same in the online qualifiers as well.

7 Likes

That’s sad! ICPC hosts and CodeChef should update this ranking algorithm. Currently, its luck based on the basis of who sees the easier problem first even if someone tries to open all the problems in different tabs. If the random selection of the first problem turns out to be earlier, you are lucky otherwise read the other question. This algorithm is slightly luck based which shouldn’t be the factor in these timed contests.

2 Likes

CodeChef can’t do anything about it. It’s the ICPC format - it’s followed at the World Finals, so it’s only fair it be applied to Online and Regional rounds, as their purpose is to determine the best team to send to World Finals.

Reading questions fast and determining time required to solve is also a skill, you may dispute its importance, but apparently the ICPC organizers think it is somewhat important.

I agree! I was unaware of this algorithm previously. But I hope they would mention explicitly somewhere in the contest page or mail for the future competitors.

It is usually mentioned on the contest page, along with all other details that people usually don’t bother to read.

Ohh so sum of all the time meant sum of time of individual correct submissions from the start time. Seriously?

I thought the sum of time between the correct submissions, and from the beginning of the contest for the first correct submission. This ultimately gives the last correct submission time as the total time taken which is generally seen in some important contests.

Anyways, can never forget this interpretation. Wasted too much time in the first question thinking it could be compensated later.