aoc2024/src/day3.rs

67 lines
1.9 KiB
Rust
Raw Normal View History

use aoc_runner_derive::{aoc, aoc_generator};
use regex::bytes::Regex;
use std::io::BufRead;
#[aoc_generator(day3)]
pub fn get_input(input: &[u8]) -> Vec<String> {
input.lines().map(|l| l.unwrap()).collect()
}
// PROBLEM 1 solution
#[aoc(day3, part1)]
pub fn part1(input: &Vec<String>) -> u64 {
let mut sum = 0u64;
let re = Regex::new(r"(?-u)mul\((\d+),(\d+)\)").unwrap();
for line in input {
let line = line.as_bytes();
for m in re.captures_iter(line) {
sum += std::str::from_utf8(&m[1]).unwrap().parse::<u64>().unwrap()
* std::str::from_utf8(&m[2]).unwrap().parse::<u64>().unwrap();
}
}
sum
}
// PROBLEM 2 solution
#[aoc(day3, part2)]
pub fn part2(input: &Vec<String>) -> u64 {
let mut sum = 0u64;
let mut do_mul = true;
let re = Regex::new(r"(?-u)(do\(\)|don't\(\)|mul\((\d+),(\d+)\))").unwrap();
for line in input {
let line = line.as_bytes();
for m in re.captures_iter(line) {
match std::str::from_utf8(&m[1]).unwrap() {
"do()" => do_mul = true,
"don't()" => do_mul = false,
_ if do_mul => {
sum += std::str::from_utf8(&m[2]).unwrap().parse::<u64>().unwrap()
* std::str::from_utf8(&m[3]).unwrap().parse::<u64>().unwrap()
}
_ => {}
}
}
}
sum
}
#[cfg(test)]
mod tests {
use crate::day3::*;
const EXAMPLE1: &[u8] = b"xmul(2,4)%&mul[3,7]!@^do_not_mul(5,5)+mul(32,64]then(mul(11,8)mul(8,5))";
const EXAMPLE2: &[u8] = b"xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))";
#[test]
fn part1_example() {
let input = get_input(EXAMPLE1);
assert_eq!(part1(&input), 161);
}
#[test]
fn part2_example() {
let input = get_input(EXAMPLE2);
assert_eq!(part2(&input), 48);
}
}