I need an optimal algorithm to find the largest divisor of a number N. Preferably in C++ or C#

Question

I am currently using the following code but its very slow for large numbers

        static int divisor(int number)
        {
            int i;
                    


        

Answer 1

You've basically hit the "factorization of large numbers" problem, which is the basis of today's Public Key encryption and is known (or hoped) to be a computationally hard problem. I indeed hope that you will not find a much better solution, otherwise the whole security infrastructure of the world will collapse... :)