5. Power of Two

If asked in a technical interview, could you write a function to determine if an integer is a power of two? For example:

Input: 1
Output: true 
Explanation: 20 = 1

Input: 16
Output: true
Explanation: 24 = 16

Input: 218
Output: false

Hints

Even though the Swift SDK has built in functionality to accomplish this task, how would you write this algorithm from scratch? Could the input values be interpreted in a different way to achieve our objective?