day02.rs

use std::fs::File;
use std::io::{BufRead, BufReader};

pub fn part1() -> i64 {
    let filename = "../input/02.txt";
    let file = File::open(filename).unwrap();
    let reader = BufReader::new(file);
    let (mut h, mut d): (i64, i64) = (0, 0);
    for line in reader.lines() {
        let line = line.unwrap();
        let parts: Vec<_> = line.split_whitespace().collect();
        let distance = parts[1].parse::<i64>().unwrap();
        match parts[0] {
            "forward" => h += distance,
            "up" => d -= distance,
            "down" => d += distance,
            _ => (),
        }
    }
    h * d
}
pub fn part2() -> i64 {
    let filename = "../input/02.txt";
    let file = File::open(filename).unwrap();
    let reader = BufReader::new(file);
    let (mut h, mut d, mut aim): (i64, i64, i64) = (0, 0, 0);
    for line in reader.lines() {
        let line = line.unwrap();
        let parts: Vec<_> = line.split_whitespace().collect();
        let distance = parts[1].parse::<i64>().unwrap();
        match parts[0] {
            "forward" => {
                h += distance;
                d += distance * aim;
            }
            "up" => aim -= distance,
            "down" => aim += distance,
            _ => (),
        }
    }
    h * d
}