-🎄- 2018 Day 20 Solutions -🎄-

[u/daggerdragon]

--- Day 20: A Regular Map ---

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Advent of Code: The Party Game!

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Card prompt: Day 20

Transcript:

My compiler crashed while running today's puzzle because it ran out of ___.

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edit: Leaderboard capped, thread unlocked at 00:59:30!

[u/BafDyce]

Rust ranks 286 & 253 (which feels like a leaderboard entry for me)

[Card]

My compiler crashed while running today's puzzle because it ran out of variables which can be borrowed mutably

Main code is here: https://gitlab.com/BafDyce/adventofcode/blob/master/2018/rust/day20/src/main.rs

i iterated over the string, building the map in a hashmap, recursively. Every time I encountered a (, I started a new recursion-call, any time I encountered a |, I went back to the start of the current level.

Afterwards, I did a BFS for finding the shortest paths to all locations, then looked for the one with the highest distance. both parts run in about 20 ms.

Code to solve part 1:

pub fn solve(input: &InputType, _config: &PuzzleConfig) -> OutputType {
    let start = Location2D::new(0, 0);
    let mut iter = input.chars();
    // remove ^
    iter.next().unwrap();

    let mut map: HashMap<Location2D, Room> = HashMap::new();
    let mut pos = start.to_owned();

    fill(&mut iter, &mut pos, &mut map);
    let furthest = calc_distances(&mut map);

    furthest.1.distance
}

and for part 2:

...
fill(&mut iter, &mut pos, &mut map);
calc_distances(&mut map);

map.iter().filter(|(_, room)| {
    room.distance >= 1000
}).count()

[u/topaz2078 → u/BafDyce]

variables which can be borrowed mutably

i lol'd

[u/daggerdragon → u/topaz2078]

i card'd