2020/rust/src/day04.rs

use std::time::{Duration, Instant};

fn between(field: &str, lower: i32, higher: i32) -> bool {
    let n: i32 = field.parse().unwrap();
    n >= lower && n <= higher
}

pub fn run(print: bool) -> Duration {
    let input = std::fs::read_to_string("../inputs/04").unwrap();

    let now = Instant::now();

    let passports: Vec<_> = input
        .split("\n\n")
        .map(|p| p.replace('\n', " ").trim().to_string())
        .collect();

    let valid_passports = passports.iter().filter(|p| {
        p.contains("byr")
            && p.contains("iyr")
            && p.contains("eyr")
            && p.contains("hgt")
            && p.contains("hcl")
            && p.contains("ecl")
            && p.contains("pid")
    });

    let mut part1 = 0;

    let part2 = valid_passports
        .filter(|p| {
            part1 += 1;

            let mut valid = true;
            for field in p.split(' ') {
                let mut parts = field.split(':');
                let label = parts.next().unwrap();
                let value = parts.next().unwrap();

                valid = valid
                    && match label {
                        "byr" => between(value, 1920, 2002),
                        "iyr" => between(value, 2010, 2020),
                        "eyr" => between(value, 2020, 2030),
                        "hgt" => {
                            let height = &value[..value.len() - 2];
                            (value.ends_with("in") && between(height, 59, 76))
                                || (value.ends_with("cm") && between(height, 150, 193))
                        }
                        "hcl" => value.starts_with("#"),
                        "ecl" => {
                            value == "amb"
                                || value == "blu"
                                || value == "brn"
                                || value == "gry"
                                || value == "grn"
                                || value == "hzl"
                                || value == "oth"
                        }
                        "pid" => value.len() == 9,
                        "cid" => true,
                        _ => false,
                    }
            }
            valid
        })
        .count();

    let elapsed = now.elapsed();
    if print {
        dbg!(elapsed, part1, part2);
    }

    elapsed
}