aka.Sohieb's blog

By aka.Sohieb, history, 2 months ago, In English,

Hi everyone!

I'm happy to invite you to join the online mirror for 2019 ICPC Malaysian National Contest (for the first time Malaysian National contest will be added to codeforces GYM).

The contest will be held on Monday, 27 May 2019.

You will have 11 problems and 5 hours to solve them.

The contest was intended for teams, but I believe it is more interesting for (Div. 1) coders if they participate individually as they will get to try all the problems.

The chief judge for the contest was asdacap. I will add the complete list for all the problem setters and which problem they created after the contest.

Thanks to Mohammad_Yasser and Boiiii for the help in preparing and testing the problems.

UPD I want to apologize for not responding to any clarification during the contest. I got an emergency 25 minutes after the contest started and I had no access to any computer for the whole day (I had to drive my father to the hospital). I'm sorry again for any contestant who asked a clarification and didn't get a response.

You can access the complete contest data from this repo, you will find the official statement, the test data and the setter solution for every problem.

The official scoreboard can be accessed from here

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By aka.Sohieb, history, 3 years ago, In English,

Hello everyone!

2 weeks ago the ACM-ICPC Arab regional contest was held.

Our Team participated in it after earning gold medals at the ECPC (3rd place).

Our Sad Story

During the contest we came upon a problem that no other team has attempted yet, and we actually submitted about 6 solutions for it, with the first two getting TLE response and the other four getting WA.

After failing to see what the problem is with our code we decided to leave it be and concern ourselves with other problems, that was nearly at minute 140.

After exactly 194 minutes from the start of the contest another team attempted the problem only to get WA. Also, at minute 214 another team (which happens to be the champion of both the ECPC and the ACPC) submitted a solution and also got a WA.

Then after a few minutes we find that there was some problems with the judge's solution and that all solutions to such problem were rejudged. This was after minute 214 of the contest (probably minute 220 or so). It turned out that our solution that we submitted at minute 90 was the correct solution, thus we were the first team to get the problem Accepted (from 4th submission, by the way).

Looking at the wasted time, that was more than 2 hours out of a 5 hour contest, which is 40% of the entire duration. We were held back for at least an hour trying to debug a solution that was already correct! and another hour until we were told that the solution was indeed correct. Not to mention the stress that we felt the entire time because at the time we decided to leave the problem be, we were in the middle of the scoreboard with only 2 problems solved while the top team solved 6 problems.

Now, 9 teams from our region have all been qualified to the WF (6 of them were Egyptians) and we weren't among them, the last team to qualify held the 13th position in the standings with 6 problems solved, while we solved 5 problems held the 15th position.

We went to the closing ceremony to see what they would do to fix the issue, but it turned out that only the judging team knew about the issue and nobody else. Not to mention that nobody apologized to our team not in the closing ceremony nor in person! :(

What we see now is that we have been screwed, and if we were given at least 30 more minutes we would have solved 2 more problems at least, because near the end of the contest we had a minor bug in a solution and only needed little more time to fix it, and another correct solution ready on paper.

We sent a complaint mail to the ACPC executive director but with no response. Then we escalated this matter to the ICPC sending another complaint mail to ( Contest Manager, Director — Regional Contests, Director — Judging, ICPC Technical Director, ICPC Deputy Executive Director, ICPC Executive Director, ACM HQ Coordinator, World Finals Director, Director, North Africa and the Middle East Contest ) but it has been 10 days and nobody responded.

Is it too hard for the ACPC judging team to make and test 12 problems in a year?!!!

Note that, this problem only got submissions before the judges fixed the issue from only 3 teams: Ours (which was affected by the issue the most), another one (which was paricipating unofficially), and the final one was the champion.

Another Note, this happened to our team 3 time this year, The first one was in the local contest, we attempted a problem and only getting WA then after the contest day we talked with the judge finding out there is a issue in the intended solution and ours was AC, but we were the 1st so that did not affect us badly. The 2nd time was in the national contest ECPC 2016 we attempted problem K only getting WA then after more than 30 minutes it become AC as there were invalid test cases, but that also did not affect us very badly as we were still held 3rd place. But the 3rd time was at the regional contest making our 2 years of training meaningless :(

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By aka.Sohieb, history, 3 years ago, In English,

Hello,

How to solve problem Odd Cycle from ACM-ICPC Asia — Daejeon regional contest.

The statement briefly:

Given simple directed graph having no self-loops or multiple edges, detect if it has any directed odd cycle (cycle with odd length) and if yes print description of an arbitrary odd cycle of the input graph.

The graph has n nodes ( n <= 100000 ) , m edges ( m <= 1000000).

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By aka.Sohieb, history, 3 years ago, In English,

Hello,

I am trying to solve 677E - Vanya and Balloons,I made almost the same solution as the tutorials mentioned. but i got WA and i do not know why, i used a stress test to find a counter-test but all random cases i generate got the correct output.

Could anyone tell what's wrong with my code 19924026 or provide a counter-test.

thanks in advance :)

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By aka.Sohieb, history, 3 years ago, In English,

I was trying to solve this problem 27E - Number With The Given Amount Of Divisors, it was said in the editorials that this is a dynamic programming problem,

but i tried to solve it using only back tracking with pruning and i got AC 19429925.

could anyone tell what is the complexity of this solution?! or how to measure the complexity of bt solutions in general?!

thanks in advance :)

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By aka.Sohieb, history, 3 years ago, In English,

I was trying to solve this problem ( Ransom Note ) but failed, i can not find any algorithm to solve this with the given constrains, and i searched for any solution to this problem but not found any.

Could anyone tell me a hint or an appropriate algorithm to solve this!!

thanks in advance :)

UPD

I solved it using a hint from jcg, and this is my code

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By aka.Sohieb, history, 4 years ago, In English,

Hello, guys!

I need help in this problem 491B - New York Hotel, there is no tutorials for this round and I can not get the idea to solve it.

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