- 953 名前：デフォルトの名無しさん mailto:sage [2019/01/27(日) 06:36:29.52 ID:rwuNPA7J.net]
- >>910 C
double abac = (bx - ax) * (cy - ay) - (by - ay) * (cx - ax);
double abad = (bx - ax) * (dy - ay) - (by - ay) * (dx - ax);
double cdca = (dx - cx) * (ay - cy) - (dy - cy) * (ax - cx);
double cdcb = (dx - cx) * (by - cy) - (dy - cy) * (bx - cx);
return (abac * abad < 0 && cdca * cdcb < 0);
