Well, there are many people who had problem with this case... i use duoble's in c++, for my gaussian elimination, and i tried many EPS but i still get WA... Something strange, is that i got AC in PKU OJ. And i suppose its because there few difficult cases there. I would like hear if someone can give me some hint, recommendation. I think it may be useless to use long long, because a hard case can overflow it. And anyway, some people seems to have gotten it AC with real's. Thanks, Eric.

Edited by author 14.04.2008 07:43

Well you can use a kind of gaussian elimination mod P with a prime P not very big ( to avoid TLE ). Thanks to Minilek. gl! Eric.



Edited by author 14.04.2008 23:52