#include "pch.h"
#include <omp.h>
#include <iostream>

constexpr auto SIZE = 5;


double getDeterminant(double matrix[][SIZE], int size) {
    double result = 0;
    double submatrix[SIZE][SIZE];

    if (size == 2)
        return ((matrix[0][0] * matrix[1][1]) - (matrix[1][0] * matrix[0][1]));
    else {
        for (int x = 0; x < size; x++) {
            int subi = 0;
            for (int i = 1; i < size; i++) {
                int subj = 0;
                for (int j = 0; j < size; j++) {
                    if (j == x)
                        continue;
                    submatrix[subi][subj] = matrix[i][j];
                    subj++;
                }
                subi++;
            }
            result = result + (pow(-1, x) * matrix[0][x] * getDeterminant(submatrix, size - 1));
        }
    }
    return result;
}


double** replaceColumn(double source[][SIZE], double column[SIZE], int pos) {
    double** result = new double*[SIZE];
    for (int i = 0; i < SIZE; i++) {
        result[i] = new double[SIZE];
    }

    for (int i = 0; i < SIZE; i++) {
        for (int j = 0; j < SIZE; j++) {
            if (j == pos) {
                result[i][j] = column[i];
            } else {
                result[i][j] = source[i][j];
            }
        }
    }

    return result;
}


int main() {
    setlocale(LC_ALL, "Russian");

    omp_set_dynamic(0);
    omp_set_num_threads(SIZE);

    double matrix[SIZE][SIZE] = {
        {4,  7,  8, 14,   0},
        {9, 66, -1, 29, -13},
        {5, -5,  0, 49,  13},
        {3, -3, 30, 60,  41},
        {1,  1,  1,  0,  47},
    };

    double coefficients[SIZE] = {
        1, 2, 3, 4, 5
    };

    double unknown[SIZE];

    double det = getDeterminant(matrix, SIZE);
    std::cout.precision(17);
    std::cout << "Детерминант общий: " << det << std::endl;

    int i;

    #pragma omp parallel for shared(matrix, coefficients, unknown) private(i)
    for (i = 0; i < SIZE; i++) {
        double** array = replaceColumn(matrix, coefficients, i);
        double temp[SIZE][SIZE];
        for (int j = 0; j < SIZE; j++) {
            for (int k = 0; k < SIZE; k++) {
                temp[j][k] = array[j][k];
            }
        }
        unknown[i] = getDeterminant(temp, SIZE);
    }


    for (int i = 0; i < SIZE; i++) {
        std::cout << "Детерминант " << i + 1 << ": " << unknown[i] << ". X" << i + 1 << ": " << unknown[i] / det << std::endl;
    }

    return 0;
}