### A.H.Ghaznavi's blog

By A.H.Ghaznavi, history, 4 months ago, ,

Hello Codeforces!

I have a programming problem form Iranian Olympiad in Informatics in type of Project Euler problems and I want you to help me for solving this problem:

Suppose that we have a $m \times n$ table that every cell of this table has filled with an integer, so that the sum of the numbers in $i$'th row of the table is $a_i$ and the sum of numbers in $i$'th column of the table is $b_i$. We say the sequence below key sequence:

$[a_1,a_2,\ldots,a_m,b_1,b_2,\ldots,b_n]$

Suppose again we write down all of the ways of filling a $5 \times 5$ table with numbers 0,1,2 so that at least one number 2 exists in the table, and calcute their key sequences. If the number of distinic sequences is $M_3$, What is the $M_3 mod \Delta$?($\Delta=10039$)

If you have a sulotion that solves this problem in less than 15 minutes, your sulotion is useful!

And like my other blog entry, sorry for my bad English!

• +16

By A.H.Ghaznavi, 14 months ago, ,

Hi!

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 (рейтинговый, Div. 1 + Div. 2, основан на Финале VK Cup 2018) 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!

• +15

By A.H.Ghaznavi, history, 18 months ago, ,

Hi!

I want to solve COCI problems but I don't know a judge that has all of the COCI problems. I want to know is there a judge except oj.uz that has all of the COCI problems?

thanks.