https://leetcode.com/problems/prime-number-of-set-bits-in-binary-representation/description/
题目大意:问L到R之间的数二进制表示的时候,1的个数是质数的个数。
解题思路:暴力
class Solution {
public int countPrimeSetBits(int L, int R) {
Set<Integer> set = new HashSet<>(Arrays.asList(2,3,5,7,11,13,17,19));
int res=0;
for(int i=L;i<=R;i++)
{
int tmp = i;
int cnt =0;
while(tmp!=0)
{
if( (tmp&1) ==1) cnt++;
tmp>>=1;
}
if(set.contains(cnt)) res++;
}
return res;
}
}