OJ Board

I've past 476 and 477 easily, but got several WA in 478...

I'm using (area(PAB) + area(PAC) + area(PBC) - area(ABC) < EPS) to judge if a point inside the triangle. Here's my code of critical session:

double triangle_area(double x0, double y0, double x1, double y1, double x2, double y2)
{
return ...