【位运算】762. Prime Number of Set Bits in Binary Representation

依次计算[L,R]内每个十进制数字所包含的二进制1的个数：

class Solution {
public:
   int  find1num(int n)
{
	int num=0;
	while(n)
	{
		num++;
		n = n&(n-1);
	}
	return num;
}
int countPrimeSetBits(int L, int R) {
     int ans=0;
     set<int> prime={2,3,5,7,11,13,17,19,23,29};
     for(int i=L;i<=R;i++)
     {
     	int num=find1num(i);
     	if(prime.count(num))
     		ans++;
     }   
     return ans;
   }

};