📚【模板】三分

难度10+大佬的讲解

对于单峰曲线，我们要用到三分。

double get(double x);
double divide(double l,double r) {
	while(fabs(r-l) >= eps) {
		double mid = (l+r)/2.0;
		double lmid = mid-eps, rmid = mid+eps;
		if(get(lmid) < get(rmid)) 
			l = mid;
		else 
			r = mid;
	}
	return get(l);
}