Как оптимизировать обращение к элементам вектора?

#include <iostream>
#include <vector>
#include <cmath>
 
/*
if((*it)->name=="Sheep" && (*it2)->name=="Wolf")
if(abs((*it)->x-(*it2)->x)<(*it)->SeeSheepRadius && abs((*it)->y-(*it2)->y)<(*it)->SeeSheepRadius){
   if((*it)->x<(*it2)->x) (*it)->dx = -0.01; else (*it)->dx = 0.01;
   if((*it)->y<(*it2)->y) (*it)->dy = -0.01; else (*it)->dy = 0.01;
}
*/
 
 
class Animal {
public:
  enum Species {
    Wolf,
    Sheep
  };
 
  Animal(Species species, double x, double y, double dx, double dy,
         double speed, double review_radius)
    : species_(species),
      x_(x), y_(y), dx_(dx), dy_(dy),
      speed_(speed), review_radius_(review_radius)
  {}
 
  Species species() const { return species_; }
  
  void setPosition(double x, double y)
  {
    x_ = x; y_ = y;
  }  
  double x() const { return x_; };
  double y() const { return y_; };
 
  void setOffset(double dx, double dy)
  {
    dx_ = dx; dy_ = dy;
  }  
 
  double dx() const { return dx_; };
  double dy() const { return dy_; };
 
  void setReviewRadius(double review_radius)
  {
    review_radius_ = review_radius;
  }
 
  bool see(const Animal& animal) {
      return (fabs(x_ - animal.x_) < review_radius_) &&
             (fabs(x_ - animal.x_) < review_radius_);
  }
  
  void escape( const Animal& animal) {
      dx_ = (x_ < animal.x_) ? -speed_ : speed_;
      dy_ = (y_ < animal.y_) ? -speed_ : speed_;
  }
 
private:
  Species species_;
  double x_;
  double y_;
  double dx_;
  double dy_;
  double speed_;
  double review_radius_;
};
 
int main() {
    std::vector<Animal> animals;
    animals.push_back(Animal(Animal::Sheep, 0.2, 0.1, 0.0, 0.0, 0.01, 1.0));
    animals.push_back(Animal(Animal::Wolf, 0.0, 0.0, 0.0, 0.0, 0.1, 1.0));
    Animal *it = &animals[0];
    Animal *it2 = &animals[1];
    
    if (it->species() == Animal::Sheep && it2->species() == Animal::Wolf && it->see(*it2) )
      it->escape(*it2);
    
    std::cout << animals[0].dx() << std::endl;
    return 0;
}