Check if a number is Bleak in C++

Here we will see whether a number is Bleak or not. A number is said to be bleak if it cannot be represented as sum of a positive number x and set bit count in x. So x + set_bit_count(x) is not equal to n , for any non-negative number x.

The concept is very simple, if the set bit count + the number is not same as the number, then that is Bleak, otherwise it is not.

Example

 Live Demo

#include <iostream>
using namespace std;
int set_bit_count(int x) {
   unsigned int bit_count = 0;
   while (x != 0) {
      x &= (x - 1);
      bit_count++;
   }
   return bit_count;
}
bool isBleakNumber(int n) {
   for (int i = 1; i < n; i++)
   if (i + set_bit_count(i) == n)
      return false;
      return true;
}
int main() {
   isBleakNumber(3) ? cout << "Yes\n" : cout << "No\n";
   isBleakNumber(4) ? cout << "Yes\n" : cout << "No\n";
}

Output

No
Yes