101 lines
2.5 KiB
Rust
101 lines
2.5 KiB
Rust
use std::str::FromStr;
|
|
|
|
use aoc_runner_derive::{aoc, aoc_generator};
|
|
|
|
#[derive(Debug, Default)]
|
|
struct Rucksack {
|
|
first_half: Vec<u8>,
|
|
second_half: Vec<u8>,
|
|
}
|
|
|
|
#[derive(Debug, Copy, Clone)]
|
|
struct NoItemInBothHalves;
|
|
|
|
#[derive(Debug, Copy, Clone)]
|
|
struct NoCommonItem;
|
|
|
|
impl Rucksack {
|
|
fn find_item_in_both_halves(&self) -> Result<u8, NoItemInBothHalves> {
|
|
self.first_half
|
|
.iter()
|
|
.copied()
|
|
.find(|item| self.second_half.contains(item))
|
|
.ok_or(NoItemInBothHalves)
|
|
}
|
|
|
|
fn has_item(&self, item: u8) -> bool {
|
|
self.first_half.contains(&item) | self.second_half.contains(&item)
|
|
}
|
|
|
|
fn find_common_item(&self, others: &[Rucksack]) -> Result<u8, NoCommonItem> {
|
|
self.first_half
|
|
.iter()
|
|
.chain(&self.second_half)
|
|
.copied()
|
|
.find(|&item| others.iter().all(|rucksack| rucksack.has_item(item)))
|
|
.ok_or(NoCommonItem)
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Copy, Clone)]
|
|
struct InvalidRucksack;
|
|
|
|
impl FromStr for Rucksack {
|
|
type Err = InvalidRucksack;
|
|
|
|
fn from_str(s: &str) -> Result<Self, Self::Err> {
|
|
let mut priorities = s
|
|
.chars()
|
|
.map(|ch| {
|
|
if !ch.is_ascii_alphabetic() {
|
|
Err(InvalidRucksack)
|
|
} else if ch.is_ascii_uppercase() {
|
|
Ok(ch as u8 - b'A' + 27)
|
|
} else {
|
|
Ok(ch as u8 - b'a' + 1)
|
|
}
|
|
})
|
|
.collect::<Result<Vec<_>, _>>()?;
|
|
let second_half = priorities.split_off(priorities.len() / 2);
|
|
Ok(Rucksack {
|
|
first_half: priorities,
|
|
second_half,
|
|
})
|
|
}
|
|
}
|
|
|
|
#[aoc_generator(day3, part1)]
|
|
fn input_generator_part1(input: &str) -> Vec<Rucksack> {
|
|
input.lines().map(|l| l.parse().unwrap()).collect()
|
|
}
|
|
|
|
#[aoc_generator(day3, part2)]
|
|
fn input_generator_part2(input: &str) -> Vec<Vec<Rucksack>> {
|
|
input
|
|
.lines()
|
|
.collect::<Vec<_>>()
|
|
.chunks(3)
|
|
.map(|list| {
|
|
list.iter()
|
|
.map(|el| el.parse().unwrap())
|
|
.collect::<Vec<_>>()
|
|
})
|
|
.collect::<Vec<_>>()
|
|
}
|
|
|
|
#[aoc(day3, part1)]
|
|
fn solve_part1(input: &[Rucksack]) -> u64 {
|
|
input
|
|
.iter()
|
|
.map(|rucksack| rucksack.find_item_in_both_halves().unwrap() as u64)
|
|
.sum()
|
|
}
|
|
|
|
#[aoc(day3, part2)]
|
|
fn solve_part2(input: &[Vec<Rucksack>]) -> u64 {
|
|
input
|
|
.iter()
|
|
.map(|rucksacks| rucksacks[0].find_common_item(&rucksacks[1..]).unwrap() as u64)
|
|
.sum()
|
|
}
|