Advent of Code 2019, day 2: Fly Me to the Moon

At 6:00 CET, the Advent of Code puzzle of day 2 became available, apparently to the enjoyment of a growing group of colleagues within Xebia. We’ve now gathered 27 colleagues on our private leaderboard — and some might also be participating without joining that board — and 20 of them have collected both stars for day 2 at this time of writing.

In addition to the expected and reasonably typical participation in Advent of Code of software developers in Xebia, people from other disciplines decided to join in the fun and challenge as well: Scrum masters, Agile coaches, product management consultants, software architects, unit managers are all solving puzzles… and today a marketing manager joined the private leaderboard as well and gained her first two stars!

Today’s challenge was to write an interpreter for a ‘program’ for a so-called Intcode computer. Programs for that computer are apparently specified as a list of instructions, all integer numbers, to be interpreted as ‘opcodes’ with arguments. The interpreter was required to execute the (still simple) instructions, with the answer to the puzzle then present at some location in the program. There was a hint to keep the interpreter’s code nearby, as it can be reused in an upcoming day.

By the way, writing an interpreter for a set of instructions has occurred in earlier seasons of Advent of Code, so it wasn’t a novel challenge. But to my surprise, this year it happened way earlier (at day 2) than in previous years: day 23 in 2015, day 12 in 2016, day 18 in 2017 and day 16 in 2018.

Unfortunately, today’s challenges also marked the point that our marketing manager programming rookie decided to skip a day. We encouraged her that she definitely should try for a comeback (and with a vengeance) tomorrow — typically the challenges are relatively independent from each other, and the challenge for day D+1 isn’t necessarily harder than day D.

According to our #codechallenges channel in Slack, only seven colleagues are still online at this moment. I guess the rest is already asleep, mentally preparing for tomorrow’s challenge, dreaming of Santa’s journey through space with Frank Sinatra singing “Fly Me to the Moon” as background music. Time to do the same.