src/2021/2/mod.rs


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pub fn part1() -> anyhow::Result<i64> {
    let mut horizontal = 0;
    let mut vertical = 0;
    for line in data_lines!()? {
        if let Some(n) = line.strip_prefix("forward ") {
            horizontal += n.parse::<i64>()?;
        } else if let Some(n) = line.strip_prefix("down ") {
            vertical += n.parse::<i64>()?;
        } else if let Some(n) = line.strip_prefix("up ") {
            vertical -= n.parse::<i64>()?;
        }
    }
    Ok(horizontal * vertical)
}

pub fn part2() -> anyhow::Result<i64> {
    let mut aim = 0;
    let mut horizontal = 0;
    let mut vertical = 0;
    for line in data_lines!()? {
        if let Some(n) = line.strip_prefix("forward ") {
            let x = n.parse::<i64>()?;
            horizontal += x;
            vertical += aim * x;
        } else if let Some(n) = line.strip_prefix("down ") {
            aim += n.parse::<i64>()?;
        } else if let Some(n) = line.strip_prefix("up ") {
            aim -= n.parse::<i64>()?;
        }
    }
    Ok(horizontal * vertical)
}

#[test]
fn test() {
    assert_eq!(part1().unwrap(), 1694130);
    assert_eq!(part2().unwrap(), 1698850445);
}