day1 part 2 (but manual parser)

This commit is contained in:
Dominic 2023-12-01 14:09:55 +01:00
parent 26134b89cd
commit 9cf3b3ef76
Signed by: msrd0
GPG key ID: DCC8C247452E98F9

View file

@ -2,13 +2,103 @@
use aoc23::read;
use chumsky::prelude::*;
use std::{io::{BufReader, BufRead}, fs::File};
use chumsky::chain::Chain;
fn parser() -> impl Parser<char, (), Error = Simple<char>> {
end()
struct Line {
first_digit: u128,
last_digit: u128
}
// thanks rust
fn array<T, const N: usize>(array: &'static [T; N]) -> &'static [T] {
array
}
impl Line {
fn parser() -> impl Parser<char, Self, Error = Simple<char>> {
choice((
// digit combinations (only the relevant ones)
just("oneight").map(|_| array(&[1, 8])),
just("twoone").map(|_| array(&[2, 1])),
just("eightwo").map(|_| array(&[8, 2])),
// single digits
just("one").or(just("1")).map(|_| array(&[1])),
just("two").or(just("2")).map(|_| array(&[2])),
just("three").or(just("3")).map(|_| array(&[3])),
just("four").or(just("4")).map(|_| array(&[4])),
just("five").or(just("5")).map(|_| array(&[5])),
just("six").or(just("6")).map(|_| array(&[6])),
just("seven").or(just("7")).map(|_| array(&[7])),
just("eight").or(just("8")).map(|_| array(&[8])),
just("nine").or(just("9")).map(|_| array(&[9])),
// garbage
none_of(['1', '2', '3', '4', '5', '6', '7', '8', '9', '\n'])
.map(|_| array(&[]))
))
.repeated()
.then_ignore(just('\n'))
.map(|digits: Vec<&'static [u128]>| {
let mut digits = digits.into_iter().flat_map(|array| array.iter().copied());
let first_digit = digits.next().expect("No digit in line");
let last_digit = digits.last().unwrap_or(first_digit);
Line {
first_digit,
last_digit
}
})
}
}
fn parser() -> impl Parser<char, Vec<Line>, Error = Simple<char>> {
Line::parser().repeated().then_ignore(end())
}
fn main() -> anyhow::Result<()> {
let _ = read("input.txt", parser())?;
let lines = read("inputs/day1.txt", parser())?;
let sum: u128 = lines
.iter()
.map(|line| line.first_digit * 10 + line.last_digit)
// .map(|number| { eprintln!("{number}"); number })
.sum();
println!("{sum}");
let mut sum: u128 = 0;
for line in BufReader::new(File::open("inputs/day1.txt")?).lines() {
let line = line?;
let line = line.trim();
if line.is_empty() {
continue;
}
let mut digits = Vec::new();
for i in 0 .. line.len() {
let s = &line[i..];
macro_rules! check_digit {
($digit:literal, $string:literal) => {
if s.starts_with(stringify!($digit)) || line[i..].starts_with($string) {
digits.push($digit);
}
}
}
check_digit!(1, "one");
check_digit!(2, "two");
check_digit!(3, "three");
check_digit!(4, "four");
check_digit!(5, "five");
check_digit!(6, "six");
check_digit!(7, "seven");
check_digit!(8, "eight");
check_digit!(9, "nine");
}
sum += digits.first().unwrap() * 10 + digits.last().unwrap();
}
println!("{sum}");
Ok(())
}