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Discussion of Problem 1828. Approximation by a Progressionsome_programming_novice Hint! // Problem 1828. Approximation by a Progression 29 Apr 2019 17:27 Let those two partial derivatives equal to zero. Felix_Mate No subject [2] // Problem 1828. Approximation by a Progression 24 Dec 2015 13:53 Edited by author 24.12.2015 20:50 Edited by author 24.12.2015 20:50 Jane Soboleva (SumNU) Re: WA 11! [1] // Problem 1828. Approximation by a Progression 24 Dec 2015 15:19 Я переписала это на джаве, используя BigInteger и BigDecimal и получила AC. (Спасибо~) Вообще, если возникают большие числа, то сейчас такие задачи легче всего решаются на джаве. UPD: Не за что~ Edited by author 25.12.2015 03:26 Felix_Mate Re: WA 11! // Problem 1828. Approximation by a Progression 24 Dec 2015 20:49 Спасибо за советы.Очень бесят задачи,где многое зависит от сложной технической реализации. waterlink wa11 [2] // Problem 1828. Approximation by a Progression 19 Mar 2011 17:42 is it a some especial test? Maxim Dvoynishnikov (Dnipropetrovsk NU) * // Problem 1828. Approximation by a Progression 25 Mar 2011 02:49 I think it's any test with N>1300. IgorKoval(from Pskov) Re: wa11 // Problem 1828. Approximation by a Progression 8 Oct 2011 01:47 YES! if you use formula n*(n-1)*(2*n-1)/6 and n is long=> overflow when n > 1300! use this: long long n; //!!! Edited by author 08.10.2011 01:48 Vasily Slesarev WA 14, please give test [1] // Problem 1828. Approximation by a Progression 1 Jul 2011 01:58 :) Thank you! Vasily Slesarev Re: WA 14, please give test // Problem 1828. Approximation by a Progression 7 Jul 2011 21:35 Now AC. The problem was with precision. Vitalii Arbuzov Someone give me AC solution please [2] // Problem 1828. Approximation by a Progression 22 Mar 2011 17:16 I've used 3 different ways to calculate simple linear regression and got 3 different wrong results. Please help. My email: Vitaly.Arbuzov@gmail.com Artem Khizha [DNU] Re: Someone give me AC solution please [1] // Problem 1828. Approximation by a Progression 24 Mar 2011 00:14 Just google the method of least squares. You derive some formulas by hand, solve small linear system and get AC. Vitalii Arbuzov Re: Someone give me AC solution please // Problem 1828. Approximation by a Progression 1 May 2011 02:26 Thanks! muhammad why wa 24? i used nested ternary search. what's the idea to solve the problem? [2] // Problem 1828. Approximation by a Progression 21 Mar 2011 17:01 i used nested ternary search on a and d but wa ( 24 when eps=1e-7 && 11 when eps<1e-7) i figured the function should be like that- f(a,d)=c1a^2+c2a+c3ad+c4d^2+c5d+c6 where c1=n && c4=n*(n-1)*(2*n-1)/6.0 here for n>1 the coefficient of a^2 and d^2 is always positive. so there should be only one(since quadratic) and low peak. so i thought ternary search would do. but why diff wa on diff value of eps. again, i found (by checking for tle) that there are high peaks as well. how can it be? perhaps, i am wrong right on the idea itself. please, guys help me find my bug. and, please tell me at least the method of solving. is it ternary search or some direct math formula or something else i am missing. if ternary search please tell me whether there is indeed high peaks and how did u deal with them... thanks in advance. Edited by author 21.03.2011 17:01 Vedernikoff 'Goryinyich' Sergey (HSE: АОП) Re: why wa 24? i used nested ternary search. what's the idea to solve the problem? [1] // Problem 1828. Approximation by a Progression 21 Mar 2011 17:35 There is closed-form solution to the problem. Read some basic econometrics textbooks, "simple linear regression" section therein. muhammad Re: why wa 24? i used nested ternary search. what's the idea to solve the problem? // Problem 1828. Approximation by a Progression 21 Mar 2011 18:21 thanks very much got ac. so simple :) bet Example [1] // Problem 1828. Approximation by a Progression 19 Mar 2011 15:39 Why in test 1 answer: 0.400 4.900 ? If b = 0.400, d = 4.900, ∑(ai − bi)^2 = 1,524. If b = 0.105263, d = 5.026316, ∑(ai − bi)^2 = 0,824 < 1,524. daftcoder [Yaroslavl SU] Re: Example // Problem 1828. Approximation by a Progression 19 Mar 2011 17:00 If b = 0.400, d = 4.900, ∑(ai − bi)^2 = 0.700
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