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