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Обсуждение задачи 1458. Военные ученияIsabelle Lightray *~ Wow // Задача 1458. Военные учения 20 ноя 2018 17:14 Very fun and interesting problem. Although, before solving it I wrote a playable version, which was pretty hard to solve by hand (brain). The problem itself isn't that hard. You don't need any deep mathematical knowledge. Just think about what the move (cross xor) means and find its relation to consequent moves player can make. It's then pretty easy to formulate several theorems that let you write an O(n^2) solution. Alexander Samal WA#1 [1] // Задача 1458. Военные учения 4 окт 2009 21:38 Help me, pls... Alexander Samal No subject // Задача 1458. Военные учения 25 окт 2009 13:35 I m sure I have right solution, but I always get WA#1... Can anybody tell me what is test #1? PSV Gimme some ideas [11] // Задача 1458. Военные учения 4 июл 2006 16:25 I can't understand how can it take 1 sec to solve for N = 1000 My biggest ideas is something like a system of equations by modulo 2, but ... Some hints please... PSV Please [10] // Задача 1458. Военные учения 5 июл 2006 05:49 Please one small pour hint PSV Re: Please [9] // Задача 1458. Военные учения 7 июл 2006 00:24 Please. I still have any ideas. May be finding of circles? WinTokk Re: Please [8] // Задача 1458. Военные учения 8 июл 2006 19:31 linear module equations will work. try to rewrite it into a simpler form and you will achieve it! SPIRiT Where can I read about solving linear module equations?(+) [7] // Задача 1458. Военные учения 27 сен 2007 21:11 I found a lot of material about modular arithmetic itself, but nothing about systems of equations modulo 2. There is a problem 1042 that I solved using an intuitive algo. But I don't have any materials about those kind of problems... Any links in Internet are available. svr Re: Where can I read about solving linear module equations?(+) [6] // Задача 1458. Военные учения 27 сен 2007 21:49 I haven't AC but sure that 1458 is a problem with great mathematical background. In matrix language Sulman command is equal to transformation of tipe A[j]*B*A[k] where A[j]=diag[1,1,1,...,-1,1,1,1,1..] So, read about minimal step of transformations to standard form. Also, sequence of such transformation is code for arbitrary 0-1 matrix. Sure that authors create the problem during reading about 0-1 matrix, transformations and coding. KAJIAIII Re: Where can I read about solving linear module equations?(+) [5] // Задача 1458. Военные учения 27 сен 2007 22:20 You're A LOOSER.I've done this program to 1 minute!!! svr Re: Where can I read about solving linear module equations?(+) [1] // Задача 1458. Военные учения 27 сен 2007 22:45 Each has It's own way and all of us are training to contests. But even after you words the problem does't seem to me as simple. Often such quick solutions depend on temporary weakeness of tests. svr Re: Where can I read about solving linear module equations?(+) // Задача 1458. Военные учения 11 янв 2009 11:29 Ac after some period! I did'n beleve that O-1 equation method can help. We have 10^6 unknowns and O(10^18) Gauss. But I had expierence for large systems with itteration method(as for Puasson eqution) and this method works here. But after I understood that the matrix of the system is nilpotent because nature of smoothing operator and itteration method has right foundation. Edited by author 10.02.2009 09:24 SPIRiT RE: program in one minute?(+) [2] // Задача 1458. Военные учения 28 сен 2007 13:48 Well, then, where is your AC for this problem? You have no AC's at all... Denis Koshman Re: RE: program in one minute?(+) [1] // Задача 1458. Военные учения 29 июл 2008 02:41 Just find a way to flip some cell without affecting others. It's easy for even N. Edited by author 03.08.2008 11:31 Fyodor Menshikov Re: RE: program in one minute?(+) // Задача 1458. Военные учения 10 фев 2009 01:00 Denis Koshman писал(a) 29 июля 2008 02:41 Just find a way to flip some cell without affecting others. Thanks! xj.ammo Timelimit at 11 with C++ [1] // Задача 1458. Военные учения 7 май 2006 16:34 Don't use IOSTREAM!!!! CSTDIO is much faster.. Denis Koshman Re: Timelimit at 11 with C++ // Задача 1458. Военные учения 29 июл 2008 02:42 and simpler ;) ftc Hint [1] // Задача 1458. Военные учения 28 июл 2008 11:47 May be it's obvious, but solution with no unnecessary moves is unique. I mean that if you get out from sequence pairs of equal moves and sort it you will get the same sequence. So you need to have 2 sequences: one transforming all to black and second - to white. Denis Koshman Re: Hint // Задача 1458. Военные учения 29 июл 2008 02:39 A good hint (though, not so obvious for me). Sergey I am trying to solve problem with recursion methods. // Задача 1458. Военные учения 26 авг 2006 04:39 Notice1: There is no differene in the order of operations. for example 1 0 than 2 3 is equal to 2 3 than 1 0 Notice 2: Same operation assumed 2*i times does not change the matrixxx. This is my thoughts. cqfwdghy how to output when no solution? [5] // Задача 1458. Военные учения 22 апр 2006 13:24 how to output when no solution? Dmitry 'Diman_YES' Kovalioff No comments (-) // Задача 1458. Военные учения 22 апр 2006 13:24 Victor Barinov (TNU) Solution is always exists (-) [3] // Задача 1458. Военные учения 27 апр 2006 14:34 Sandro (USU) Re: Solution is always exists (-) [2] // Задача 1458. Военные учения 5 май 2006 08:48 What is the answer for test: 3 WWW WBW WWW ? GaLL [Tyumen SU] Re: Solution is always exists (-) [1] // Задача 1458. Военные учения 5 май 2006 15:15 N is even. Sandro (USU) Re: Solution is always exists (-) // Задача 1458. Военные учения 5 май 2006 21:21 Thanks! Orenburg SU 7 Very intersting problem [1] // Задача 1458. Военные учения 25 апр 2006 01:49 I think 3 hours to got AC Zeva [USU] Re: Very intersting problem // Задача 1458. Военные учения 26 апр 2006 20:06 I completely agree with you. Edited by author 26.04.2006 20:09
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