leetcode Power of Two位运算

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

Credits:
Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.

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可以直接做：

class Solution {public:bool isPowerOfTwo(int n) {if (n < 1) return false;int res;while (n>0){res = n % 2;if (res != 0){if (n == 1)return true;elsereturn false;}n = n / 2;}}};

也可以用位运算：

class Solution {public:bool isPowerOfTwo(int n) {if (n < 1) return false;    return !(n&(n-1));}};