nroot_functia

long long nroot(int N, long long A)
{
    if(A<0) A=-A;
    if(A==0 || A==1 )
        return A;
    double xPre = rand() % 10;
    double eps = 1e-3;
    double delX = LLONG_MAX;
    double xK;
    while (delX > eps)
    {
        xK = ((N - 1.0) * xPre + (double)A/pow(xPre, N-1)) / (double)N;
        delX = abs(xK - xPre);
        xPre = xK;
    }
    return (long long)xK;

}