#include <iostream>
#include <iomanip>
#include <string>
#include <ctime>
#include <cstdlib>
#include <fstream>
#include <omp.h>

using namespace std;

int *arr_sum(const int *a, const int *b, int N) {
    int *c = new int[N];
    for (int i = 0; i < N; i++)
        c[i] = a[i] + b[i];

    return c;
}

int *arr_sum_par(const int *a, const int *b, int N) {
    int *c = new int[N];
    int i = 0;

    omp_set_dynamic(0);
    int nThreads = omp_get_max_threads();
    if (!nThreads) nThreads = 2;
    omp_set_num_threads(nThreads);

    #pragma omp parallel shared(a, b, c) private(i, N)
    {
        #pragma omp parallel for
        for (i = 0; i < N; i++)
            c[i] = a[i] + b[i];
    }

    return c;
}

void print_arr(string filename, int *arr, int N) {
    ofstream out(filename);
    for (int i = 0; i < N; i++)
        out << arr[i] << " ";
    out << endl;
    out.close();
}

int main() {
    srand(time(NULL));

    int N = 50000;
    int *a = new int[N];
    int *b = new int[N];
    int *c = nullptr;

    for (int i = 0; i < N; i++) {
        a[i] = rand() % N;
        b[i] = rand() % N;
    }

    double start = clock()/(double)CLOCKS_PER_SEC;
    c = arr_sum(a, b, N);
    double finish = clock()/(double)CLOCKS_PER_SEC;
    const double time1 = finish - start;

    print_arr("sum.txt", c, N);
    delete[] c;

    start = clock()/(double)CLOCKS_PER_SEC;
    c = arr_sum_par(a, b, N);
    finish = clock()/(double)CLOCKS_PER_SEC;
    const double time2 = finish - start;

    print_arr("sum_par.txt", c, N);
    delete[] c;

    cout << "time1: " << time1 << endl;
    cout << "time2: " << time2 << endl;

    delete[] a;
    delete[] b;

    return 0;
}