231. Power of Two

Given an integer, write a function to determine if it is a power of two.

class Solution {public:    bool isPowerOfTwo(int n) {        int s = 0;        if(n < 1) return false;        for(int i = 0; i < 32; ++i){            if(n & 1)                ++s;            n >>= 1;        }        if(s == 1)            return true;        return false;    }};