Usu's blog

By Usu, history, 5 years ago, In English

Hello! I hope you're all safe in this hard time!

I want to announce that our contest AGM (6th edition) has just ended this weekend. We want to offer you the possibility to see the problems and compete virtually! The difficulty of the rounds is the same as an ICPC, regional stage. AGM was organized and prepared by these marvelous lads: patrick.sava (the hearth of the project), george_stelian, Stelutzu, PlayLikeNeverB4, geniucos, average_frog_enjoyer, munteanuvlad98, Alex18mai, bogdan10bos, teoionescu, carabet.cosmin, Stefan_Radu, Mihai22e, Mihneac, vreaudelftpls, eman98 and GinguIonut.

Qualification

Final Round Day1

Final Round Day2

Our website

AGM Facebook

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By Usu, history, 5 years ago, In English

! registrations have been extended: until 7th February 23:59

Dear friends, I am honored to present you Adolescent Grigore Moisil International Programming Contest. AGM is addressed to high school students who can team up in teams up to 3 members, ICPC style. The contest has a qualification round on 8th February and an on-site round in Bucharest (Romania) on 28-29 March. The problems are set up fully by university students, medalists in national and international competitions (IOI,BOI,CEOI...). We are looking forward to international participants, especially those who want to participate in the final round in Bucharest. You can register here until 6th February.

Finally, I am more than delighted to present you our technical and scientifical team: patrick.sava (the heart of the project), george_stelian , PlayLikeNeverB4 , geniucos , theodor.moroianu , average_frog_enjoyer , munteanuvlad98 , Alex18mai , teoionescu , bogdan10bos , carabet.cosmin , Stefan_Radu , Mihai22e , Mihneac , vreaudelftpls , eman98 , GinguIonut.

More details here: https://agm-contest.com/

Also, don't hesitate to contact us: [email protected]

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By Usu, history, 6 years ago, In English

Hey! Does anybody have a solution in n log n for this? Given n rectangles, determinate a point which is included by a maximum number of rectangles (including the boundaries).

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By Usu, history, 6 years ago, In English

Hey! Does anybody know how to solve this? Given n segments, count how many pairs of segments have a common point. There are no 2 overlapping segments and the segments are can make any angle with the origin of the cartesian plane.

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By Usu, history, 6 years ago, In English

Hey! Can anybody help with this problem? This problem says that we are in a point (x,y) and we have n lines (defined by the line's equation a,b,c). How many lines can we see from that point? If we see only a point of a line, we do not consider that line at all. I think we should find the intersections of all the lines firstly, but I do not have certain ideas. The number of lines is 10.000, does anybody have ideas?

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By Usu, history, 6 years ago, In English

Hey! I discovered a type of problems where we have for example n points and we want to discover the convex hull (the border) using some of those points, but after that calculate the area of the smallest rectangle in which that convex hull can lie inside. I saw that we can rotate the convex hull with some degrees, but I didn't understand it very well. Can anybody give me more details about how to rotate a convex hull with sin and cos, some links eventually. Thanks!

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By Usu, history, 6 years ago, In English

Hi! Is anybody who can give me a solution for this? We have an array with n elements and a number k. We are asked to calculate in how many continuous strings of size exactly k (k is even), the element at the i-th position is in the second half if we sort that continuous string (all values are different). We want to calculate this value for every single position*. Example: n=6, k=4, the array: 1 4 2 5 9 3, the output will be like this: 0 1 0 3 2 0

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By Usu, history, 6 years ago, In English

Hey! I have a question. If I have to calculate a pow b modulo mod, with b>mod, is it the same with a pow (b % (mod-1)?

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By Usu, history, 6 years ago, In English

Hi! I encounter difficulties in understanding a well known fact in number theory. Given a number n, in how many ways can we write n as a sum of numbers? Exemple: 4 -> ( 4 ) ( 1 3 ) ( 2 2 ) ( 1 1 2 ) ( 1 1 1 1 ) Many thanks for those who can help me

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By Usu, history, 6 years ago, In English

Hey guys, I am returning to you with a problem. Given n numbers a1 a2.. an, find the substring (some consecutive nummbers) with the maximum xor string.

I know that we must use a trie, but I don't really know how. Can anybody explain me please?

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By Usu, history, 6 years ago, In English

Hey guys, can anybody explain me well how can we find (and when we can't find) (x,y) such a*x + b*y = c?

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By Usu, history, 7 years ago, In English

Hey guys! I need your help. Lately I tried to make a program which check if a point is inside o polygon, I did it in N^2 for convex, I didn't find a brute force for concave. So if you can help me, I would be grateful for an implementation or a link for concave (brute force) and an implementation for faster running time, I know the idea behind it, but my implementation have some bugs and I want to see a corect one. That from geeksforgeeks is not correct if you think about it. Thanks in advance!

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By Usu, history, 7 years ago, In English

Hey, I am encountering difficulties with this problem: http://codeforces.net/contest/919/problem/D from yesterday contest. This is my code commented. Can anybody tell me what is wrong with my logic? My first failed test case is #6, I count more than I should. code : http://codeforces.net/contest/919/submission/34816679

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By Usu, history, 7 years ago, In English

Hey guys! Lately I tried to understand more about game theory, but I have some uncertainties. Does anybody have a good article or a good explanation regarding Staircase Nim and the relation between Sprague-Grundy and mex()?

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By Usu, history, 7 years ago, In English

Hey guys, can you please give me some sources with easy BIT 2D implementation? I would be grateful also for some problems using this from easy to hard. Thanks in advance!

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By Usu, history, 7 years ago, In English

Hey guys, recently I started to deepen algorithmic science. I relised that dynamics include a huge amount of techniques and approaches, I know some of them, but I'm not good at dinamycs with bits/masks for example. I don't know also many things in combinatorics like "the number of sequences such that their sum is t" which is 2^(t-1), not really this, but combinatorics like this. So I'm asking you for help. Can you give me please some useful links or name of methods? I would be greatful.

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