# greatest common divisor

## Greatest Common Divisor

In mathematics, the greatest common divisor (gcd) of two or more integers, which are not all zero, is the largest positive integer that divides each of the integers. For example, the gcd of 8 and 12 is 4.

The greatest common divisor is also known as the greatest common factor (gcf), highest common factor (hcf), greatest common measure (gcm), or highest common divisor.

Source:https://en.wikipedia.org/wiki/Greatest_common_divisor

## Check for the gcd

Write a `getGCD`

function that takes two numbers as parameters and returns the gcd.

### Sample Input and Output

Input: 8 12 Output: 4

### Optimization

Check out Euclid's algorithm and see how much things speed up. How can you account for this in terms of time complexity?

See:

https://en.wikipedia.org/wiki/Euclidean_algorithm#Worked_example

https://en.wikipedia.org/wiki/Greatest_common_divisor#Complexity_of_Euclidean_method