day1/src/main.rs

use regex::Regex;
use phf::phf_map;

static NUMBERS: phf::Map<&'static str, u8> = phf_map! {
    "zero" => 0,
    "one" => 1,
    "two" => 2,
    "three" => 3,
    "four" => 4,
    "five" => 5,
    "six" => 6,
    "seven" => 7,
    "eight" => 8,
    "nine" => 9,
    "0" => 0,
    "1" => 1,
    "2" => 2,
    "3" => 3,
    "4" => 4,
    "5" => 5,
    "6" => 6,
    "7" => 7,
    "8" => 8,
    "9" => 9,
};


fn main() {
    let first_and_last_digits: Regex = Regex::new(r"(zero|one|two|three|four|five|six|seven|eight|nine|[0-9]).*(zero|one|two|three|four|five|six|seven|eight|nine|[0-9])").unwrap();
    let only_one_digit: Regex = Regex::new(r"([0-9])").unwrap();
    let input = include_str!("../input.txt");

    let mut vals: Vec<u16> = vec![];

    for line in input.split('\n') {
        if line == "" {
            continue;
        }

        let result = first_and_last_digits.captures(line);

        let group1;
        let group2;

        if let Some(captured) = result {
            [group1, group2] = captured.extract().1;
        } else {
            [group1] = only_one_digit.captures(line).expect("Line did not have a capture").extract().1;
            group2 = group1;
        }

        let first_digit = NUMBERS.get(group1).expect("Regex group 1 and phf hashmap were mismatched");
        let last_digit = NUMBERS.get(group2).expect("Regex group 2 and phf hashmap were mismatched");

        vals.push((first_digit * 10 + last_digit).into());
    }

    println!("{}", vals.into_iter().fold(0, | acc, curr | acc + curr));
}