A.H.Ghaznavi's blog

By A.H.Ghaznavi, 8 months ago, In English,


Recently, a question has been created for me. Every minute how many scores you have lost from each problems? You have ever thought of this if you start solving problems in contest from C or D how much does your score change?

It's means that unlike the usual you solve problem (for example) in order C,B,A and then go other problems. We know every minute some score have lost from every problem. For example in Codeforces Round #504 (rated, Div. 1 + Div. 2, based on VK Cup 2018 Final) for problem A and B every minute, two points deducted and for problem C every minute every minute, six points deducted. Suppose that Amir (a person!) solved A,B and C in this contest. But we have a question : which order to solve problems is better? Suppose again Amir solved problem A in a minutes, solve B in b minutes and solve C in c minutes. If he solved this problems in order A,B,C then he lost 2a scores for problem A and 2(a + b) scores for problem B and 6(a + b + c) scores for problem C. It means that he lost 10a + 8b + 6c score in sum (without consider wrong submissions!). But if he solved problems in this order: C,B,A. With some calculations we understand that he lost 2a + 4b + 10c. Now If (2a + 4b + 10c) < (10a + 8b + 6c) then the second order is better. It means if c < 2a + b it was better Amir solved problem C at first!

Now I want to know " Every minute how many scores you have lost from each problems? " to plan that "Which problem is better for solve at first?". If we know that we can plan better for the contest! So I request to declare this before all of the contests.

And at the end I want to thanks from Mahdi Ghaznavi (mahdigh) for this blog's idea and sorry for my bad English!

Thanks for reading!

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8 months ago, # |
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If problem A gives pa points initially and takes ta minutes, while problem B pb and tb, then you should solve A first if .

I created a not-easy problem about it once: http://codeforces.com/contest/657/problem/D.