把

while(l<=r)

改成

const double eps=1e-10;

while(r-l>eps)

邪道乱搞，以后可能被hack

double f(double s){
	if(s-(int)s>=0.95)return(int)s+1;
	if(s-(int)s<=0.05)return(int)s;
	return s;
}