OJ Board

I got too many WA for the problem 10180 , but when i changed my
long double temp = acos(temp1) ;
to
long double temp = acos((temp1) <? 1 >? -1);
i get it Accepted :D

some other advices :
1 - use the epsilon 1e-7
2 - use long double
3 - use your own less function instead of <
for example :
bool less ...