OJ Board

Thanks a lot for help. Both algos were good. The problem was precision.
When I used double instead of float I got accepted.

Can anyone tell me what's wrong?

area_r = (2 * acos(0)) * (area/(n*tan((2 * acos(0))/n)));
area_R = (2 * acos(0)) * 2*area/(n*sin(2*(2 * acos(0))/n));

spectators = area_R - area;
officials = area - area_r;

that's my algo, which works fne for test cases, but I receive WA...

OK - I tried 2*acos(0) - and for all test cases worked fine, but, still got WA. And I have no idea why. Can anyone send me more test cases?

I have encountered following problem:
I cannot use M_PI defined in math. In the description is:
more less PI = 2 * cos^-1 (0)
How to code it? I tried 2/cos(0) but it didn't work.
And I tried also #define PI = 3.14159265358979323846,
but it didn't work either (example set works fine but I've got WA)