65 lines
1.7 KiB
Rust
65 lines
1.7 KiB
Rust
#![forbid(elided_lifetimes_in_paths, unsafe_code)]
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use aoc23::read;
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use chumsky::prelude::*;
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struct Line {
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first_digit: u128,
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last_digit: u128
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}
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// thanks rust
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fn array<T, const N: usize>(array: &'static [T; N]) -> &'static [T] {
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array
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}
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impl Line {
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fn parser() -> impl Parser<char, Self, Error = Simple<char>> {
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choice((
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// digit combinations (only the relevant ones)
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just("oneight").map(|_| array(&[1, 8])),
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just("twone").map(|_| array(&[2, 1])),
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just("eightwo").map(|_| array(&[8, 2])),
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// single digits
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just("one").or(just("1")).map(|_| array(&[1])),
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just("two").or(just("2")).map(|_| array(&[2])),
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just("three").or(just("3")).map(|_| array(&[3])),
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just("four").or(just("4")).map(|_| array(&[4])),
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just("five").or(just("5")).map(|_| array(&[5])),
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just("six").or(just("6")).map(|_| array(&[6])),
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just("seven").or(just("7")).map(|_| array(&[7])),
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just("eight").or(just("8")).map(|_| array(&[8])),
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just("nine").or(just("9")).map(|_| array(&[9])),
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// garbage
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none_of(['1', '2', '3', '4', '5', '6', '7', '8', '9', '\n'])
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.map(|_| array(&[]))
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))
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.repeated()
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.then_ignore(just('\n'))
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.map(|digits: Vec<&'static [u128]>| {
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let mut digits = digits.into_iter().flat_map(|array| array.iter().copied());
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let first_digit = digits.next().expect("No digit in line");
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let last_digit = digits.last().unwrap_or(first_digit);
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Line {
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first_digit,
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last_digit
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}
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})
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}
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}
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fn parser() -> impl Parser<char, Vec<Line>, Error = Simple<char>> {
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Line::parser().repeated().then_ignore(end())
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}
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fn main() -> anyhow::Result<()> {
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let lines = read("inputs/day1.txt", parser())?;
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let sum: u128 = lines
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.iter()
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.map(|line| line.first_digit * 10 + line.last_digit)
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.sum();
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println!("{sum}");
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Ok(())
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}
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