double average(vector<double> v)
{
if (v.size() == 0) return 0;
double sum = 0;
for (int i = 0; i < v.size(); i++)
sum = sum + v[i];
return sum / v.size();
}
void raise_by_percent(vector<double>& v, double p)
{
for (int i = 0; i < v.size(); i++)
v[i] =v[i] * (1 + p / 100);
}