Thursday Code Puzzler: Minimum Difference

It's Thursday, so it's time for another code puzzler. The idea is simple: solve the coding problem as efficiently as you can, in any language or framework that you find suitable.

Note: Even though there really is nothing stopping you from finding a solution to this on the internet, try to keep honest, and come up with your own answer.  It's all about the participation!

Find the Minimum Difference

Given two arrays, sorted and exactly the same length, write a function that finds a pair of numbers - one from each of the arrays - such that the difference between both is as small as possible. 

Catch up on all our previous puzzlers here