#include <iostream>
#include <cstdlib>        // rand
#include <ctime>          // time
#include <sys/time.h>     // gettimeofday

class Timer
{
private:
    timeval t1, t2;
public:
    Timer() {}
    ~Timer() {}
    void start() { gettimeofday(&t1, NULL); }
    void stop() { gettimeofday(&t2, NULL); }
    double elapsedTime() { return (t2.tv_sec - t1.tv_sec)*1000.0 + (t2.tv_usec - t1.tv_usec)/1000; }
};

template<typename T>
class Vector
{
private:
    T *data;
    const size_t num;
public:
    Vector(const size_t num) : num(num) { data = new T[num]; }
    ~Vector() { delete[] data; }
    inline T& operator() (const size_t i) { return data[i]; }
    inline const T& operator() (const size_t i) const { return data[i]; }
    size_t size() const { return num; }
};

template<typename T>
class Matrix
{
private:
    T *data;
    const size_t nrows, ncols;
public:
    Matrix(const size_t nr, const size_t nc) : nrows(nr), ncols(nc) { data = new T[nrows * ncols]; }
    ~Matrix() { delete[] data; }
    inline T& operator() (const size_t r, const size_t c) { return data[c*nrows + r]; }
    inline const T& operator() (const size_t r, const size_t c) const { return data[c*nrows + r]; }
    size_t size1() const { return nrows; }
    size_t size2() const { return ncols; }
};

inline double rand_double(double min=0.0, double max=1.0)
{
    return (max - min) * (static_cast<double>(rand()) / RAND_MAX) + min;
}

int main() {
    // seed random number generator
    srand( static_cast<unsigned int>(time(NULL)) );

    // intialize data
    const int m = 1000, n = 40000;
    Matrix<double> A(m,n);
    Vector<double> B(m);
    for(size_t i=0; i<A.size1(); i++) {
        B(i) = rand_double();
        for(size_t j=0; j<A.size2(); j++) {
            A(i,j) = rand_double();
        }
    }

    // measure timing
    Timer timer;
    timer.start();

    // in MATLAB: count = sum(bsxfun(@ne, A, B))
    Vector<double> count(n);
    #pragma omp parallel for
    for(int j=0; j<n; ++j) {
        count(j) = 0.0;
        for(int i=0; i<m; i++) {
            count(j) += (A(i,j) != B(i));
        }
    }

    timer.stop();

    // elapsed time in milliseconds
    std::cout << "Elapsed time is " << timer.elapsedTime() << " milliseconds." << std::endl;

    return 0;
}