| Day | Title | Code | Tests | Tags | Difficulty | Visual |
|---|---|---|---|---|---|---|
| Day 1 | Trebuchet?! | code | tests | numbers spelled with letters | 🍪🍪 | |
| Day 2 | Cube Conundrum | code | tests | min num of cubes to win | 🍪️ | |
| Day 3 | Gear Ratios | code | tests | parse numbers, number couples based on center coordinate | 🍪️ | |
| Day 4 | Scratchcards | code | tests | list intersection, pow2, wins win more cards | 🍪 | |
| Day 5 | If You Give A Seed A Fertilizer | code | tests | ranges of longs, number mappings | 🍪🍪 | |
| Day 6 | Wait For It | code | tests | optimise time based on init speed | 🍪 | |
| Day 7 | Camel Cards | code | tests | poker, hand types, jolly card | 🍪🍪 | |
| Day 8 | Haunted Wasteland | code | tests | network with l/r, period, lcm | 🍪 | |
| Day 9 | Mirage Maintenance | code | tests | arithmetic sequence, recursion, prev and next in sequence | 🍪🍪 | |
| Day 10 | Pipe Maze | code | tests | pipe maze, flood | 🍪🍪🍪 | image |
| Day 11 | Cosmic Expansion | code | tests | manhattan distance, row/col expansion | 🍪🍪 | |
| Day 12 | Hot Springs | code | tests | strings with wildcards | 🍪🍪🍪 | |
| Day 13 | Point of Incidence | code | tests | coords, mirrored maps, almost identical strings | 🍪🍪️ | |
| Day 14 | Parabolic Reflector Dish | code | tests | coords, tilting board, period | 🍪🍪️ | |
| Day 15 | Lens Library | code | tests | hashes, lists | 🍪🍪️ | |
| Day 16 | The Floor Will Be Lava | code | tests | coords | 🍪🍪️ | |
| Day 17 | Clumsy Crucible | code | tests | best path | ||
| Day 18 | Lavaduct Lagoon | code | tests | coords, draw ring, flood-fill, shoelace | 🍪🍪️🍪🍪 | |
| Day 19 | Aplenty | code | tests | connected true/false rules, recursion, combinations | 🍪🍪️🍪 | test input diagram - real input diagram (monstrous) |
| Day 20 | Pulse Propagation | code | tests | directed graph, pulses, dfs | 🍪🍪️🍪️🍪️🍪️ | |
| Day 21 | Step Counter | code | tests | reachable plots with N steps, infinite grid, | 🍪🍪️🍪️🍪 | |
| Day 22 | Sand Slabs | code | tests | Basically Tetris & Jenga had a baby | 🍪🍪️🍪🍪 | |
| Day 23 | A Long Walk | code | tests | Grid, DFS | 🍪🍪🍪🍪🍪 | |
| Day 24 | Never Tell Me The Odds | code | tests | 3d coords, skew lines, linear equations and matrices | 🍪🍪️🍪🍪️ | |
| Day 25 | Snowverload | code | tests |
