The earliest memory I have of ‘programming’ is in the early/mid 90s when my father brought home a computer from work. We could play games on it … so of course I took the spreadsheet program he used (LOTUS 123, did I date myself with that?) and tried to modify it to print out a helpful message for him. It … halfway worked? At least I could undo it so he could get back to work…

After that, I picked up programming for real in QBASIC (I still have a few of those programs lying around), got my own (junky) Linux desktop from my cousin, tried to learn VBasic (without a Windows machine), and eventually made it to high school… In college, I studied computer science and mathematics, mostly programming in Java/.NET, although with a bit of everything in the mix. A few of my oldest programming posts on this blog are from that time.

After that, on to grad school! Originally, I was going to study computational linguistics, but that fell through. Then programming languages (the school’s specialty). And finally I ended up studying censorship and computer security… before taking a hard turn into the private sector to follow my PhD advisor.

Since then, I’ve worked in the computer security space at a couple of different companies. Some don’t exist any more, some you’ve probably heard of. I still program for fun too, and not just in security.

But really, I still have a habit of doing a little bit of everything. Whatever seems interesting at the time!

AoC 2018 Day 13: Mine Cart Madness

2018-12-13

Source: Mine Cart Madness

Part 1: Load a minecart track that looks like this:

/->-\
| | /—-
| /-+–+-\ | | | | | v | -+-/ -+–/ -—–/

AoC 2018 Day 12: Fat Cellular Automaton

2018-12-12

Source: Subterranean Sustainability

Part 1: Create an infinite 2D cellular automaton with transition rules based on two points to each side, starting with initial state at index 0 to the right.

After 20 generations, what is the sum of indexes of points turned on?

AoC 2018 Day 11: Gridlocked Fuel

2018-12-11

Source: Chronal Charge

Part 1: Define a grid as follows (x,y coordinates + a constant C):

r(x) = x + 10
G(x, y) = hundreds(r(x) * (r(x) * y + C)) - 5

Find the 3x3 area in a 300x300 grid with the highest total G(x, y) .

AoC 2018 Day 10: It's Full of Stars!

2018-12-10

Source: The Stars Align

Part 1: Given a system of moving particles (with position and velocity) find the point where the particles spell a message. What is that message?

AoC 2018 Day 9: Marble Madness

2018-12-09

Source: Marble Mania

Part 1: Place marbles in a circle such that each marble is placed by skipping one place except for marbles divisible by 23. For those, don’t place them, skip back 7 places, and remove that marble as well. Add these two marbles to your current score.

Given a specific player count and last marble, what’s the highest score?

AoC 2018 Day 8: Checksum Treeification

2018-12-08

Source: The Sum of Its Parts

Part 1: A custom tree data structure is defined as:

child count
metadata count
child count additional subtrees (recursive)
metadata count metadata nodes

Calculate the sum of all metadata nodes.

AoC 2018 Day 7: Job Simulator

2018-12-07

Source: The Sum of Its Parts

Part 1: Given a list of job dependencies (job A must be before job B), determine the order jobs must be done in. Break ties lexicographically.

AoC 2018 Day 6: Infinite Area Simulator

2018-12-06

Source: Chronal Coordinates

Part 1: Given a list of points, calculate the region of points closest to each point (using Manhattan distance). Return the size of the largest non-infinite region.

AoC 2018 Day 5: Alchemical reduction

2018-12-05

Source: Alchemical Reduction

Part 1: Given a string, reduce it by removing pairs of letters that are the same letter but different cases. Repeat until you have a minimal string.

AoC 2018 Day 4: Sleeping on the job

2018-12-04

Source: Repose Record

Part 1: Given a log of guard shifts and times asleep/awake, calculate the guard that was asleep most often and which minute they were most asleep for.