LeetCode #231 - Power of Two

题目描述：

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

Example 1:

Input: 1
Output: true 
Explanation: 2^0 = 1

Example 2:

Input: 16
Output: true
Explanation: 2^4 = 16

Example 3:

Input: 218
Output: false

判断一个数是否为2的幂，直接不断除2，判断最后是否为1.

class Solution {
public:
    bool isPowerOfTwo(int n) {
        while(n>=2)
        {
            if(n%2==1) return false;
            n=n/2;
        }
        return n==1;
    }
};