#include <iostream>
#include <cmath>
#include <vector>
#include <algorithm>
#include <chrono>

using namespace std::chrono;
using namespace std::literals;
using matrix = std::vector<std::vector<double>>;

std::vector<double> iterationMethod(const matrix& A, const std::vector<double>& b)
{
    for (int j = 0; j < A.size(); ++j)
    {
        double sum = 0;

        for (int i = 0; i < A.size(); ++i)
        {
            if (j != i)
            {
                sum += A[j][i];
            }
        }

        if (sum >= std::abs(A[j][j]))
        {
            throw std::runtime_error("wrong matrix");
        }
    }

    matrix C = A;
    std::vector<double> F = b;

    for (int j = 0; j < C.size(); ++j)
    {
        for (int i = 0; i < C.size(); ++i)
        {
            if (j == i)
            {
                C[j][i] = 0;
            }
            else
            {
                C[j][i] /= A[j][j];
                C[j][i] *= -1;
            }
        }
    }

    for (int i = 0; i < F.size(); ++i)
    {
        F[i] /= A[i][i];
    }

    std::vector<double> prev(b.size(), 0);
    std::vector<double> cur(b.size(), 0);
    double maxDif = 0;
    double accuracy = 0.001f;

    do
    {
        prev = cur;
        maxDif = 0;

        for (int j = 0; j < C.size(); ++j)
        {
            double sum = 0;

            for (int i = 0; i < C.size(); ++i)
            {
                sum += C[j][i] * prev[i];
            }

            cur[j] = sum + F[j];
        }

        for (int i = 0; i < cur.size(); ++i)
        {
            double dif = std::abs(cur[i] - prev[i]);

            if (dif > maxDif)
            {
                maxDif = dif;
            }
        }
    }
    while (maxDif > accuracy);

    return cur;
}

int main()
{
    std::vector<double> res = iterationMethod(m, b);

    time_point<high_resolution_clock> endTime = clock.now();

    std::cout << "Result = { ";

    for (auto& i : res)
    {
        std::cout << i << " ";
    }

    std::cout << "}" << std::endl;

    return 0;
}