Math one poj 3372 contest4

#include <iostream> 
#include <cstdio> 
  
using namespace std; 
  
int main() 
{ 
    int n; 
    while(scanf("%d", &n)!= EOF) 
    { 
        if (!(n&(n-1))) 
        { 
            printf("YES\n"); 
        } 
        else
            printf("NO\n"); 
    } 
} 
证明：http://www.cnblogs.com/Saatgut/archive/2008/10/09/1307405.html