Follow up to the Diagonals Problem

In my solution to the diagonals problem, I felt like I wasn't able to adequately explain how I got from the numbers to the final equations. This is because I'm not too sure myself, it was the product of trial-and-error, luck and a bit of inspiration.

In his post, Tim does a great job of showing his thinking that led him to the same formula I got. Also, he posted code to a python program that takes the dimensions of the grid as input and returns the number of squares the diagonal crosses. The trickiest part of the program was the helper function for determining the greatest common factor of m and n. I hadn't thought that far... I was hoping python would have a built-in function for that!

This will be my last post for the course. It was interesting, challenging and I feel well prepared for CSC 236 next semester. I'm a bit embarrassed that I forgot how to take derivatives during the final, but I'm going to chalk that up to exam time stress.

Thanks for reading!