This year, again, December starts with the Advent of Code puzzles. Eric Wastl announced that from this year the puzzle series last only 12 days instead of the 25. In the previous years I felt exhausted by the end of the month so I don't mind that this year ends earlier.

Puzzles

Between December 1 and December 12, a programming puzzle appears every day on the Advent of Code website. Each problem has two parts, the second part unlocks after you complete the first. To understand each day's puzzle, go to the website and read the full description (for example Day 1: Secret Entrance).

Spoiler alert: If you still plan to work on the puzzles, stop reading now.

Highlights

For the sixth consequtive year, I write my solutions in Clojure. Since I don't use this language professionally, I look forward to coding in Clojure every December. Usually, I solved the day's problem before leaving to work, though sometimes I polished my code in the evening.

I sought external help to solve the second parts of Day 7 and Day 10 and I haven't yet started Day 12. The other days went smoothly. I particularly enjoyed Day 6 which required reading the input file from right to left, to satisfy to the Elf's clumsy specification.

You can find my solutions on GitHub.

Acknowledgments

Thanks Eric Wastl for creating and running Advent of Code.