| ENG RUS | Timus Online Judge |
Discussion of Problem 1686. Photovoltaic SpaceshipNickC8 Can you give some tests? [2] // Problem 1686. Photovoltaic Spaceship 13 Oct 2013 04:47 Can you give some tests? The stars coordinates aren't natural numbers? NickC8 Re: Can you give some tests? [1] // Problem 1686. Photovoltaic Spaceship 13 Oct 2013 05:51 Why precision of 10^-5 is needed? Should the algorithm ignore cases when scalar product of normal vector of the plane and "star"-vector is negative (the angle between vectors will be 90<x<270 so star's rays won't reach solar battery of esp. this plane)? ASK Re: Can you give some tests? // Problem 1686. Photovoltaic Spaceship 20 Apr 2018 01:52 Integer output also works, but you need int64_t. Note that it is not enough for normal/star angle to be less than pi/2, you also need to have correct normal -- the one that is opposite to the fourth vertex. BVitaly Why 2800 instead of 1400??? [3] // Problem 1686. Photovoltaic Spaceship 28 Feb 2009 15:05 Why 2800 instead of 1400??? 21*1m^2+21*1m^2+1358*1m^2=1400 Watts Gevorgyan Aram Re: Why 2800 instead of 1400??? [2] // Problem 1686. Photovoltaic Spaceship 28 Feb 2009 15:29 because your answer must multiply on 2. Gevorgyan Aram Re: Why 2800 instead of 1400??? [1] // Problem 1686. Photovoltaic Spaceship 28 Feb 2009 15:33 Why 2800 instead of 1400??? 21*1m^2+21*1m^2+1358*1m^2=1400 Watts can you tell me your algoritm songaal Re: Why 2800 instead of 1400??? // Problem 1686. Photovoltaic Spaceship 10 Mar 2009 18:00 Because you agreed that you would inflate the result twofold. Read the man-in-black's offer again. Sfairat WA#6 [2] // Problem 1686. Photovoltaic Spaceship 1 Mar 2009 21:22 I use such an algorithm:I take four normal vectors to four different surfaces of the "ship" as cross product of two vectors,which I take as two vectors between points creating these surfaces.The length of this vector is 2xsquare of the triangle created by these points. Then,as energy produced by one surface of the "ship" for one star can be counted as square(sq further) of the surface multiplied by length of the "star" vector and multiplied by absolute of cos between normal vector to the surface and "star" vector. abs of that cosinus is equal to abs of their scalar production divided by their length production.As sq*"star" vector length multiplied by 2 is equal to their length production,then the energy produced by one surface is equal to abs of their scalar production divided by 2.It's quite clear that if we sum energies produced by all surfaces we'll get 2x energy that's really got from this star,so we don't need to multiply it by 2 lately to get the power wished by "man in black".So,if we sum energies from all the stars we'll get resulting energy. I have checked and rechecked this algorithm several times,I also have rechecked the program several times,but I Haven't found any mistakes not in the program,nor in the algorithm,I also ran several tests and checked the results manually,so I'll be grateful to anyone who'll show me possible mistakes. Edited by author 01.03.2009 21:35 Laise Re: WA#6 [1] // Problem 1686. Photovoltaic Spaceship 2 Mar 2009 20:30 To find answer we realy need to find sum of all scalar products of normals and star vectors (its absolute values of course), then divide 2 and print out... I did it with long long - not int and not double Sfairat Re: WA#6 // Problem 1686. Photovoltaic Spaceship 3 Mar 2009 16:12 I replaced int by long long and got the right result^_^ I have thought,for some reason,that int type'd be enough for summary power. Sfairat WA#6 // Problem 1686. Photovoltaic Spaceship 1 Mar 2009 21:22 Sorry 4 multi-posting Edited by author 01.03.2009 21:25
|