Question

how to convert n into an integer m that can be represented in the form 2^x+2^y (where x and y are non-negative integers such that x???y)

Answer 1

In this you will get an idea on how to implement the abover format:

bool isPower(unsigned n)

{

   if (n==1)  return true;

   // Try all numbers from 2 to sqrt(n) as base

   for (int x=2; x<=sqrt(n); x++)

   {

       unsigned y = 2;

       unsigned p = pow(x, y);

       // Keep increasing y while power 'p' is smaller

       // than n.

       while (p<=n && p>0)

       {

           if (p==n)

               return true;

           y++;

           p = pow(x, y);

        }

   }

   return false;

}