NOTES.txt

Parse a string with numbers into ints:

    let parts: Vec<usize> = line
            .split_whitespace()
            .map(|x| x.parse::<usize>().unwrap())
            .collect();


Parse a whole line like "Card 1: 17  1 24 40  8 | 55 27 89 9 64"

    fn parse(line: &str) -> Self {
        let (card, (winners, have)) = line
            .strip_prefix("Card ")
            .and_then(|s| s.split_once(':'))
            .and_then(|(card, rest)| Option::Some((card, rest.split_once('|').unwrap())))
            .unwrap();
        Self {
            number: card.parse::<usize>().unwrap(),
            winners: winners
                .split_whitespace()
                .map(|x| x.parse::<usize>().unwrap())
                .collect(),
            have: have
                .split_whitespace()
                .map(|x| x.parse::<usize>().unwrap())
                .collect(),
        }
    }

Find an element of a vector that matches a condition:

    let mapping: &ElementMapping =
            mappings.iter().find(|&m| m.from == elem).unwrap();