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## Discussion of Problem 1265. Mirror

WA #8
Posted by Lightweight! Lightweight baby! 10 Aug 2004 03:12
I get WA #8 and I suppose it's because of the precision.
I tried rotating everything so that the mirror becomes (0,0) -> (L,0) actually using sin and cos and got WA #8.
I tried finding out the relative coordonates without actually using rotations (using distances) and got WA at even lower tests (4 or 5).
Can anybody help me with some hints? Should i try it in pascal with the extended type? Or anybody that got AC in C please help.
I used long arithmetics (+)
Posted by Vladimir Yakovlev (USU) 10 Aug 2004 12:07
All calculations can be done in integers. 100-digit numbers are quite enough.
Re: I used long arithmetics (+)
Posted by Lightweight! Lightweight baby! 10 Aug 2004 12:47
But don't you need sqrt (and maybe division too)? Or you did those on large numbers as well?
Re: I used long arithmetics
Posted by Vladimir Yakovlev (USU) 10 Aug 2004 14:18
I don't need division and sqrt, only addition, subtraction and multiplication.
I got it now. Thank you (-)
Posted by Lightweight! Lightweight baby! 10 Aug 2004 16:50
I've got AC without long number arithmetics - just don't use rotation (-)
Posted by Dmitry 'Diman_YES' Kovalioff 10 Aug 2004 17:09
Didn't work for me (+)
Posted by Scythe (Berinde Radu) 10 Aug 2004 21:02
I tried using double and no rotations. Actually the exact operations i did on long nombers and got AC, but on double (only add, sub and mul). It didn't work. Maybe with pascal's extended it does.
How?
Posted by Maigo Akisame (maigoakisame@yahoo.com.cn) 15 Sep 2004 20:15
AC. Just trouble.
Posted by Maigo Akisame (maigoakisame@yahoo.com.cn) 24 Sep 2004 20:31