https://todd.ginsberg.com/post/advent-of-code/2018/
- Day 9 (ring data structure)
- Day 10 (finding smallest area tip)
- Day 11 (summed-area table)
- Day 12 (part 2 tip)
- Day 15 (path generation)
- Day 17 (water propagation)
- Day 19 (part 2 tip)
- Day 20 (path generation)
- Day 21 (logic)
- Day 22 (part 2 tip)
- Day 25 (part 1 tip)
Special hat-tip to https://github.com/ephemient/aoc2018 for Day 23 part 2!