---cargo
[profile.dev]
opt-level = 3

[dependencies]
nalgebra = "0.34"
---

use nalgebra::DMatrix;
use std::collections::HashMap;

static CONTENT: &'static str = include_str!("./inputs/11_1.txt");

fn main() {
    let parts: HashMap<[char; 3], (usize, Vec<[char; 3]>)> = CONTENT.lines().map(|l| l.trim()).map(|p| {
        let (key, rest) = p.split_once(':').unwrap();
        let key = key.trim();
        let rest = rest.trim();

        let key: [char; 3] = core::array::from_fn(|idx| key.chars().nth(idx).unwrap());
        let rest: Vec<[char; 3]> = rest.split(' ').map(|p| {
            core::array::from_fn(|idx| p.chars().nth(idx).unwrap())
        }).collect();

        (key, rest)
    }).chain([(['o', 'u', 't'], Vec::new())]).enumerate().map(|(idx, (key, v))| (key, (idx, v))).collect();

    println!("{:?}", parts);

    let mut adj_matrix = DMatrix::from_element(parts.len(), parts.len(), 0u64);

    for (src, (src_idx, targets)) in parts.iter() {
        for dest_idx in targets.iter().map(|t| parts.get(t).map(|(i, _)| i).unwrap()) {
            adj_matrix[(*src_idx, *dest_idx)] = 1;
        }
    }

    println!("{}", adj_matrix);

    let you_idx: usize = parts.get(&['y', 'o', 'u']).map(|(idx, _)| *idx).unwrap();
    let out_idx: usize = parts.get(&['o', 'u', 't']).map(|(idx, _)| *idx).unwrap();

    let mut total_routes = 0;

    let mut connectivity_matrix = DMatrix::identity(parts.len(), parts.len());
    for length in 1..=parts.len() {
        println!("Length: {:?}", length);
        connectivity_matrix *= &adj_matrix;

        let routes: u64 = connectivity_matrix[(you_idx, out_idx)];
        println!("Routes: {}", routes);

        total_routes += routes;
    }

    println!("Total Routes: {}", total_routes);
}