struct SparseElement {
    int Col;
    double Entry;
};

struct SparseRow {
    bool FindElement(UINT Col, SparseElement* &Output);
    Vector<SparseElement> Data;
};

class SparseMatrix {
public:
    void Init(UINT _Size);
    void PushElement(UINT Row, UINT Col, double Entry);
    void Transpose(SparseMatrix &O);

    Vector<SparseRow> Rows;
    UINT Size;
};

void Multiply(Vector<double> &Output, SparseMatrix &M, Vector<double> &V);
void Multiply(Vector<double> &Output, double D, Vector<double> &V);
void Multiply(Vector<double> &Output, Vector<double> &V, double D);
double Multiply(Vector<double> &L, Vector<double> &R);
void Add(Vector<double> &Output, Vector<double> &L, Vector<double> &R);
void Subtract(Vector<double> &Output, Vector<double> &L, Vector<double> &R);