231. Power of Two

/*Given an integer, write a function to determine if it is a power of two.判断一个数是否为2的幂*/class Solution {public:    bool isPowerOfTwo(int n) {        if(n<=0) return false;        int cnt=0;        for(int i=0;i<32;i++)        {            cnt += n&1;            n>>=1;        }        return cnt==1 ? true : false;    }    bool isPowerOfTwo2(int n) {        if(n<=0) return false;        return !(n&(n-1));    }};