AoC2021/src/day08.rs

use crate::Day;

pub struct Day08(Vec<(Vec<String>, Vec<String>)>);

impl Day for Day08 {
    fn init(content: String) -> anyhow::Result<Self> {
        let x = content.lines().map(foo).collect::<Vec<(Vec<String>, Vec<String>)>>();
        Ok(Self(x))
    }

    fn part1(&self) -> anyhow::Result<String> {
        let mut count = 0;
        for (_, b) in &self.0 {
            let l = b.iter().map(String::len).filter(|n| (*n == 2) || (*n == 4) || (*n == 3) | (*n == 7)).count();
            count += l;
        }

        Ok(format!("{}", count))
    }

    fn part2(&self) -> anyhow::Result<String> {
        Ok(format!("{}", self.0.iter().cloned().map(do_stuff).collect::<anyhow::Result<Vec<i32>>>()?.iter().sum::<i32>()))
    }
}

fn do_stuff((input, output): (Vec<String>, Vec<String>)) -> anyhow::Result<i32> {
    let out = output.iter().map(|x| get_char(&input, x.clone())).collect::<anyhow::Result<Vec<_>>>()?.join("");

    out.parse().map_err(anyhow::Error::new)
}

fn get_char(input: &[String], s: String) -> anyhow::Result<String> {
    let one = input.iter().cloned().find(|x| x.len() == 2).ok_or_else(|| anyhow::Error::msg("could not find one"))?.chars().collect::<Vec<char>>();
    let four = input.iter().cloned().find(|x| x.len() == 4).ok_or_else(|| anyhow::Error::msg("could not find one"))?.chars().collect::<Vec<char>>();
    let chars = s.chars().collect::<Vec<char>>();
    let x = match s.len() {
        2 => "1",
        3 => "7",
        4 => "4",
        5 => match chars.iter().filter(|x| !one.contains(*x)).count() {
            3 => "3",
            _ => match chars.iter().filter(|x| !four.contains(*x)).count() {
                3 => "2",
                _ => "5",
            }
        },
        6 => match chars.iter().filter(|x| !one.contains(*x)).count() {
            5 => "6",
            _ => match chars.iter().filter(|x| !four.contains(*x)).count() {
                2 => "9",
                _ => "0",
            }
        }
        _ => "8",
    };
    Ok(x.to_string())
}

fn foo(st: &str) -> (Vec<String>, Vec<String>) {
    let z = st.split('|').collect::<Vec<_>>();
    let input = z[0];
    let output = z[1];
    (input.split_whitespace().map(String::from).collect(), output.split_whitespace().map(String::from).collect())
}

#[cfg(test)]
mod tests{
    use crate::Day08;
    use crate::day::Day;

    const INPUT: &str = r"be cfbegad cbdgef fgaecd cgeb fdcge agebfd fecdb fabcd edb | fdgacbe cefdb cefbgd gcbe
edbfga begcd cbg gc gcadebf fbgde acbgfd abcde gfcbed gfec | fcgedb cgb dgebacf gc
fgaebd cg bdaec gdafb agbcfd gdcbef bgcad gfac gcb cdgabef | cg cg fdcagb cbg
fbegcd cbd adcefb dageb afcb bc aefdc ecdab fgdeca fcdbega | efabcd cedba gadfec cb
aecbfdg fbg gf bafeg dbefa fcge gcbea fcaegb dgceab fcbdga | gecf egdcabf bgf bfgea
fgeab ca afcebg bdacfeg cfaedg gcfdb baec bfadeg bafgc acf | gebdcfa ecba ca fadegcb
dbcfg fgd bdegcaf fgec aegbdf ecdfab fbedc dacgb gdcebf gf | cefg dcbef fcge gbcadfe
bdfegc cbegaf gecbf dfcage bdacg ed bedf ced adcbefg gebcd | ed bcgafe cdgba cbgef
egadfb cdbfeg cegd fecab cgb gbdefca cg fgcdab egfdb bfceg | gbdfcae bgc cg cgb
gcafb gcf dcaebfg ecagb gf abcdeg gaef cafbge fdbac fegbdc | fgae cfgab fg bagce";

    #[test]
    fn part1_test() -> anyhow::Result<()>{
        let d = Day08::init(INPUT.to_string())?;
        assert_eq!("26", d.part1()?);
        Ok(())
    }

    #[test]
    fn part2_test() -> anyhow::Result<()>{
        let d = Day08::init(INPUT.to_string())?;
        assert_eq!("61229", d.part2()?);
        Ok(())
    }

    #[test]
    fn part1_real() -> anyhow::Result<()> {
        let d = Day08::init(crate::load_input("08")?)?;
        assert_eq!("479", d.part1()?);
        Ok(())
    }

    #[test]
    fn part2_real() -> anyhow::Result<()> {
        let d = Day08::init(crate::load_input("08")?)?;
        assert_eq!("1041746", d.part2()?);
        Ok(())
    }
}