feat: Add Advent of Code 2024 Day 20 🎄

scala/hack-by-example/readme.md

@@ -30,12 +30,13 @@ Advent of Code 2024
 | 🟢[Day 11][AoC2024-11] ([Solution][Sol-AoC2024-11])  | Apply rules to a set of numbers. Two good solutions, one is a nice example of memoization.                                          |
 | 🔶[Day 12][AoC2024-12] ([Solution][Sol-AoC2024-12])  | Finding disjoint sets (using union-find or merge-find) to calculate perimeters or sides of garden plots in a 2D map.                |
 | 🔶[Day 13][AoC2024-13] ([Solution][Sol-AoC2024-13])  | Miniature linear algebra, finding integer solutions to two equations.                                                               |
-| 🔶[Day 14][AoC2024-14] ([Solution][Sol-AoC2024-14])  | 💜Robots moving around a grid given a starting point and vector.  Find the pretty picture they make.                                |
+| 🔶[Day 14][AoC2024-14] ([Solution][Sol-AoC2024-14])  | 💜️ Robots moving around a grid given a starting point and vector.  Find the pretty picture they make.                              |
 | 🟥[Day 15][AoC2024-15] ([Solution][Sol-AoC2024-15])  | A Robot pushing movable boxes in a 2D warehouse, where boxes can push other boxes.                                                  |
 | 🔶[Day 16][AoC2024-16] ([Solution][Sol-AoC2024-16])  | Find the minimum cost path through a maze, then all minimum cost paths. BFS and directional map.                                    |
 | 🟥[Day 17][AoC2024-17] ([Solution][Sol-AoC2024-17])  | Make a simple CPU with opcodes and operands to find the output, then study the input program to make a quine. Lots of bit fiddling. |
-| 🟢[Day 18][AoC2024-18] ([Solution][Sol-yAoC2024-18]) | 💜️Simple BFS pathfinding through a grid (without drawing a plan), then a binary search to find the first blocked path.             |
-| 🟢[Day 19][AoC2024-19] ([Solution][Sol-yAoC2024-19]) | 💜️Splitting a design into valid towels, using memoization.                                                                         |
+| 🟢[Day 18][AoC2024-18] ([Solution][Sol-AoC2024-18]) | 💜️ Simple BFS pathfinding through a grid (without drawing a plan), then a binary search to find the first blocked path.            |
+| 🟢[Day 19][AoC2024-19] ([Solution][Sol-AoC2024-19]) | 💜️ Splitting a design into valid towels, using memoization.                                                                        |
+| 🟢[Day 20][AoC2024-20] ([Solution][Sol-AoC2024-20]) | Running a maze choosing when some walls can disappear.                                                                              |
 
 [AoC2024-01]: https://adventofcode.com/2024/day/1
 [AoC2024-02]: https://adventofcode.com/2024/day/2