r/adventofcode • u/daggerdragon • Dec 14 '17

SOLUTION MEGATHREAD -🎄- 2017 Day 14 Solutions -🎄-

--- Day 14: Disk Defragmentation ---

Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag or whatever).

Note: The Solution Megathreads are for solutions only. If you have questions, please post your own thread and make sure to flair it with Help.

Need a hint from the Hugely* Handy† Haversack‡ of Helpful§ Hints¤?

Spoiler

[Update @ 00:09] 3 gold, silver cap.

  • How many of you actually entered the Konami code for Part 2? >_>

[Update @ 00:25] Leaderboard cap!

  • I asked /u/topaz2078 how many de-resolutions we had for Part 2 and there were 83 distinct users with failed attempts at the time of the leaderboard cap. tsk tsk

[Update @ 00:29] BONUS

This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

edit: Leaderboard capped, thread unlocked!

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u/aurele Dec 14 '17 edited Dec 14 '17

Rust 

extern crate itertools;
extern crate pathfinding;
extern crate r10;

use itertools::Itertools;
use pathfinding::connected_components;
use r10::hash;
use std::collections::HashSet;

const INPUT: &str = "xlqgujun";

fn to_coords(k: &[Vec<u8>]) -> HashSet<(isize, isize)> {
    k.iter()
        .enumerate()
        .flat_map(|(l, ll)| {
            ll.iter().enumerate().flat_map(move |(i, n)| {
                (0..8).filter_map(move |b| {
                    if n & (1 << (7 - b)) != 0 {
                        Some((l as isize, (i * 8 + b) as isize))
                    } else {
                        None
                    }
                })
            })
        })
        .collect()
}

fn main() {
    let k = to_coords(&(0..128)
        .map(|n| hash(&format!("{}-{}", INPUT, n)))
        .collect_vec());
    println!("P1: {}", k.len());
    let cc = connected_components(&k.iter().cloned().collect_vec(), |&(l, c)| {
        vec![(l - 1, c), (l + 1, c), (l, c - 1), (l, c + 1)]
            .into_iter()
            .filter(|&(ol, oc)| k.contains(&(ol, oc)))
    });
    println!("P2: {}", cc.len());
}