#include <cmath>
#include <vector>

//From http://www.richelbilderbeek.nl/CppSolveQuadratic.htm
const std::vector<double> SolveQuadratic(const double a, const double b, const double c)
{
  if (a == 0.0) 
  {
    if (b == 0.0) 
      return std::vector<double>(1,0.0);
    else
      return std::vector<double>(1,c/b);
  }
  const double d = (b * b) - (4.0 * a * c);
  if (d < 0.0) 
    return std::vector<double>();
  if (d == 0.0) 
    return std::vector<double>(1,-b/(2.0*a));
  const double rD = std::sqrt(d);
  std::vector<double> solutions;
  solutions.reserve(2);
  solutions.push_back((-b + rD)/(2.0 * a));
  solutions.push_back((-b - rD)/(2.0 * a));
  return solutions;
}