src/bin/day1.rs


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static DAY: u8 = 1;

fn main() {
    let input = advent::read_lines(DAY);
    println!("{DAY}a: {}", list_distance(&input));
    println!("{DAY}b: {}", 0);
}

fn list_distance(numbers: &[String]) -> u32 {
    let mut list1 = Vec::new();
    let mut list2 = Vec::new();
    for pair in numbers {
        let (number1, number2) = pair.split_once("   ").unwrap();
        list1.push(number1.parse::<u32>().unwrap());
        list2.push(number2.parse::<u32>().unwrap());
    }
    list1.sort();
    list2.sort();

    list1.iter()
         .enumerate()
         .map(|(i, number1)| number1.abs_diff(list2[i]))
         .sum()
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test() {
        let input = [
            "3   4",
            "4   3",
            "2   5",
            "1   3",
            "3   9",
            "3   3",
        ].iter().map(|&x| String::from(x)).collect::<Vec<_>>();
        assert_eq!(list_distance(&input), 11);
    }
}