advent-of-code/2023/rust/src/day1.rs

use crate::prelude::*;

mod prelude;

fn main() {
    Day1::show(day_input(1), day_input(1))
}

struct Day1 {}
impl Day1 {
    fn calibration_value(line: &str) -> i128 {
        println!("{line}");
        let bytes = line.as_bytes();
        let mut first_digit: Option<u8> = None;
        let mut last_digit: Option<u8> = None;
        for i in 0..bytes.len() {
            let n = bytes.len() - 1 - i;
            println!("{n} {i}");
            if first_digit.is_none() && (0x30..=0x39).contains(&bytes[i]) {
                first_digit = Some(bytes[i] - 0x30);
                println!("found first {first_digit:?}");
            }
            if last_digit.is_none() && (0x30..=0x39).contains(&bytes[n]) {
                last_digit = Some(bytes[n] - 0x30);
                println!("found last {last_digit:?}");
            }
            if first_digit.is_some() && last_digit.is_some() {
                break;
            }
        }
        println!("{:?} {:?}", first_digit, last_digit);
        Into::<i128>::into(first_digit.or(last_digit).unwrap() * 10)
            + Into::<i128>::into(last_digit.or(first_digit).unwrap())
    }

    fn num_name(s: &[u8]) -> Option<u8> {
        for (i, w) in [
            "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine",
        ]
        .map(|s| s.as_bytes())
        .iter()
        .enumerate()
        {
            if s.starts_with(w) {
                return Some(i as u8);
            }
        }
        return None;
    }

    fn num_name_end(s: &[u8]) -> Option<u8> {
        for (i, w) in [
            "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine",
        ]
        .map(|s| s.as_bytes())
        .iter()
        .enumerate()
        {
            if s.ends_with(w) {
                return Some(i as u8);
            }
        }
        return None;
    }

    fn calibration_value_words(line: &str) -> i128 {
        println!("{line}");
        let bytes = line.as_bytes();
        let mut first_digit: Option<u8> = None;
        let mut last_digit: Option<u8> = None;
        for i in 0..bytes.len() {
            let n = bytes.len() - 1 - i;
            println!("NI: {n} {i}");
            if first_digit.is_none() {
                if (0x30..=0x39).contains(&bytes[i]) {
                    first_digit = Some(bytes[i] - 0x30);
                    println!("found first {first_digit:?}");
                } else if let Some(n) = Self::num_name(&bytes[i..]) {
                    first_digit = Some(n);
                    println!("found first text {first_digit:?}");
                }
            }
            if last_digit.is_none() {
                println!("{:?}", &bytes[..=n]);
                if (0x30..=0x39).contains(&bytes[n]) {
                    last_digit = Some(bytes[n] - 0x30);
                    println!("found last {last_digit:?}");
                } else if let Some(n) = Self::num_name_end(&bytes[..=n]) {
                    last_digit = Some(n);
                    println!("found last text {last_digit:?}");
                }
            }
            if first_digit.is_some() && last_digit.is_some() {
                break;
            }
        }
        println!("{:?} {:?}", first_digit, last_digit);
        Into::<i128>::into(first_digit.or(last_digit).unwrap() * 10)
            + Into::<i128>::into(last_digit.or(first_digit).unwrap())
    }
}

impl AoCSolution for Day1 {
    type Input = String;
    type Solution = i128;

    fn part1(input: Self::Input) -> Self::Solution {
        input.lines().map(Self::calibration_value).sum()
    }

    fn part2(input: Self::Input) -> Self::Solution {
        input.lines().map(Self::calibration_value_words).sum()
    }
}

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

    #[test]
    fn test() {
        assert_eq!(
            Day1::part1(
                r#"1abc2
pqr3stu8vwx
a1b2c3d4e5f
treb7uchet"#
                    .into()
            ),
            142
        );
        assert_eq!(
            Day1::part2(
                r#"two1nine
eightwothree
abcone2threexyz
xtwone3four
4nineeightseven2
zoneight234
7pqrstsixteen"#
                    .into()
            ),
            281
        );
    }
}