https://github.com/wrightdylan/advent-of-code-2025

🎄 Advent of Code 2025 in Rust 🎄
https://github.com/wrightdylan/advent-of-code-2025

advent-calendar advent-of-code advent-of-code-2025 aoc aoc-2025 aoc-2025-in-rust code-challenges problem-solving rust rust-lang

Last synced: 19 days ago
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🎄 Advent of Code 2025 in Rust 🎄

• Host: GitHub
• URL: https://github.com/wrightdylan/advent-of-code-2025
• Owner: wrightdylan
• License: gpl-3.0
• Created: 2025-11-29T17:03:51.000Z (6 months ago)
• Default Branch: main
• Last Pushed: 2025-12-15T10:01:37.000Z (6 months ago)
• Last Synced: 2025-12-27T04:10:23.990Z (5 months ago)
• Topics: advent-calendar, advent-of-code, advent-of-code-2025, aoc, aoc-2025, aoc-2025-in-rust, code-challenges, problem-solving, rust, rust-lang
• Language: Rust
• Homepage: https://adventofcode.com/2025
• Size: 67.4 KB
• Stars: 0
• Watchers: 0
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# :gift::christmas_tree: Advent of Code 2025 :christmas_tree::sparkles:

These are my solutions to this year's [Advent of Code](https://adventofcode.com/2025/).

Solutions make use of `cargo-aoc` code helper ([here](https://github.com/gobanos/cargo-aoc)).

## Solutions

All solutions linked below:

| Day | Title | 1 :star: | 2 :star: | Solution | Rating |

|:-|:-|:-|:-|:-|:-|

| [01](https://adventofcode.com/2025/day/1)  | Secret Entrance                 | 5.49µs | 27.0µs | [day01.rs](./src/day01.rs) | :sunglasses: |

| [02](https://adventofcode.com/2025/day/2)  | Gift Shop                       | 17.4ms | 34.0ms | [day02.rs](./src/day02.rs) | :smirk: |

| [03](https://adventofcode.com/2025/day/3)  | Lobby                           | 168µs  | 2.86ms | [day03.rs](./src/day03.rs) | :astonished: |

| [04](https://adventofcode.com/2025/day/4)  | Printing Department             | 3.45ms | 12.6ms | [day04.rs](./src/day04.rs) | :persevere: |

| [05](https://adventofcode.com/2025/day/5)  | Cafeteria                       | 298µs  | 8.43µs | [day05.rs](./src/day05.rs) | :scream: |

| [06](https://adventofcode.com/2025/day/6)  | Trash Compactor                 | 3.57µs | 72.8µs | [day06.rs](./src/day06.rs) | :no_mouth: |

| [07](https://adventofcode.com/2025/day/7)  | Laboratories                    | 102µs  | 275µs  | [day07.rs](./src/day07.rs) | :anguished: |

| [08](https://adventofcode.com/2025/day/8)  | Playground                      | 2.53ms | 4.35ms | [day08.rs](./src/day08.rs) | :confounded: |

| [09](https://adventofcode.com/2025/day/9)  | Movie Theater                   | 130µs  | 2.12ms | [day09.rs](./src/day09.rs) | :cry: |

| [10](https://adventofcode.com/2025/day/10) | Factory                         | 1.10ms | 59.7ms | [day10.rs](./src/day10.rs) | :angry: |

| [11](https://adventofcode.com/2025/day/11) | Reactor                         | 4.88µs | 42.3µs | [day11.rs](./src/day11.rs) | :fearful: |

| [12](https://adventofcode.com/2025/day/12) | Christmas Tree Farm             | 6.34µs | :gift: | [day12.rs](./src/day12.rs) | :grimacing: |

## Notes

1. I'll revisit day 2 again as I think I can improve the algorithm.

2. It took a few optimisations to get day 3 part 2 to single digit ms.

3. Solutions should be run in both development and release profiles to see timing differences.

4. Day 4 part 2 was a tough one to run in parallel.

5. Day 5 initially required 4.9TB of RAM. Fortunately there was another data structure to the rescue.

6. Day 6 part 1 was pretty standard. Part 2 could have been easier, but I wanted a unified solution for both parts.

7. I sometimes struggle with recursive functions.

8. Day 8 had far too many false starts.

9. Day 9, part 2, could possibly run a bit faster by using [coordinate compression](https://medium.com/algorithms-digest/coordinate-compression-2fff95326fb).

10. Day 9, part 2, now incorporates coordinate compression. This has dropped run time from 378ms to 2.12ms. The original took 19s single threaded.

11. Major dislike of having to resort to using z3.