Given an integer `n`, return `true` if it is a power of two. Otherwise, return `false`.
An integer `n` is a power of two if there exists an integer `x` such that `n == 2^x`.
**Example 1:**
```
Input: n = 1
Output: true
Explanation: 2^0 = 1
```
**Example 2:**
```
Input: n = 16
Output: true
Explanation: 2^4 = 16
```
**Example 3:**
```
Input: n = 3
Output: false
```
Could you solve it without loops/recursion using bit manipulation?