public static double[] solve(double[][] A, double[] B)// KOD z neta
    {
        int N = B.length;
        for (int k = 0; k < N; k++)
        {
            /** find pivot row **/
            int max = k;
            for (int i = k + 1; i < N; i++)
                if (Math.abs(A[i][k]) > Math.abs(A[max][k]))
                    max = i;

            /** swap row in A matrix **/
            double[] temp = A[k];
            A[k] = A[max];
            A[max] = temp;

            /** swap corresponding values in constants matrix **/
            double t = B[k];
            B[k] = B[max];
            B[max] = t;

            /** pivot within A and B **/
            for (int i = k + 1; i < N; i++)
            {
                double factor = A[i][k] / A[k][k];
                B[i] -= factor * B[k];
                for (int j = k; j < N; j++)
                    A[i][j] -= factor * A[k][j];
            }
        }

        /** Print row echelon form **/
//        printRowEchelonForm(A, B);

        /** back substitution **/
        double[] solution = new double[N];
        for (int i = N - 1; i >= 0; i--)
        {
            double sum = 0.0;
            for (int j = i + 1; j < N; j++)
                sum += A[i][j] * solution[j];
            solution[i] = (B[i] - sum) / A[i][i];
        }
        return solution;
        /** Print solution **/
//        printSolution(solution);
    }