text: #ifndef HELLO_WORLD_SPARSEVECTOR_H
  #define HELLO_WORLD_SPARSEVECTOR_H
  
  #include <vector>
  #include <memory>
  
  using namespace std;
  
  class SparseVector {
  public:
      SparseVector(vector<int> dimensions, vector<double> values);
      double angle(const SparseVector& other) const;
      double magnitude() const;
      double dot(const SparseVector& other) const;
  
  protected:
      vector<int> dimensions;
      vector<double> values;
  };
  
  #endif //HELLO_WORLD_SPARSEVECTOR_H
  