Corporate Policy

Advent of Code 2015 Day 11

Part 1

1. Subtleties in the password rules
2. Practicing my ABC's

Subtleties in the password rules

one increasing straight of at least three letters

Could be four?
Could be five?

at least two different, non-overlapping pairs of letters

Could be three?

Are these passwords valid?

• aabbccde: no i,o,l, three different, non-overlapping pairs, one increasing straight of at least three letters
• abcdeeff: no i,o,l, two different, non-overlapping pairs, one increasing straight of five letters

Good to know when determining my new password.

Practicing my ABC's

Let's try figuring this out manually, frame-by-frame.

I was pretty certain I found it:

Sadly, that's not the correct answer to Part 1.

I re-traced my steps, and realized I overlooked an earlier password:

Thankfully, that was the correct answer to Part 1!

Part 2

I think I already know this answer!

Because, thanks to my overlooking Part 1's answer, I already discovered it!

Indeed, the password I thought was Part 1's answer is Part 2's answer!

I did it!!

• I solved both parts!
• Unknowingly, in reverse order!
• Without writing an algorithm, (un?)fortunately!

That's three parts in a row that I haven't written an algorithm to solve a puzzle.

I realize that is often the purpose of these puzzles: to do so using a codified algorithm.

But, as my series title states:

• My sole intent is to solve them
• Not to solve them solely by writing an algorithm

Because sometimes the most efficient - or fun - way to solve these is not by writing, but by some other equally creative means!