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make day 5 faster

This commit is contained in:
2024-12-05 18:40:12 +01:00
parent b5bcc8268f
commit ab88556e4c

View File

@@ -1,4 +1,5 @@
use itertools::Itertools;
use std::str::FromStr;
use std::{cmp::Ordering, fs::read_to_string};
pub fn day_main() {
@@ -8,21 +9,21 @@ pub fn day_main() {
println!(" part2: {}", part2(input));
}
type RiddleResult = usize;
type R = usize;
fn part1(input: &str) -> RiddleResult {
fn part1(input: &str) -> R {
let (rules, books) = parse(input);
books
.iter()
.filter(|book| valid_book(book, &rules))
.map(|book| book[book.len() / 2].parse::<RiddleResult>().unwrap())
.map(|book| book[book.len() / 2])
.sum()
}
fn valid_book(book: &[&str], rules: &[(&str, &str)]) -> bool {
fn valid_book(book: &[R], rules: &[(R, R)]) -> bool {
for (i, a) in book.iter().enumerate() {
for b in book.iter().skip(i + 1) {
if rules.contains(&(b, a)) {
if rules.contains(&(*b, *a)) {
return false;
}
}
@@ -30,36 +31,37 @@ fn valid_book(book: &[&str], rules: &[(&str, &str)]) -> bool {
true
}
fn parse(input: &str) -> (Vec<(&str, &str)>, Vec<Vec<&str>>) {
fn parse(input: &str) -> (Vec<(R, R)>, Vec<Vec<R>>) {
let (a, b) = input.split_once("\n\n").unwrap();
let rules = a
.lines()
.map(|line| line.split_once("|").unwrap())
.map(|(a, b)| (R::from_str(a).unwrap(), R::from_str(b).unwrap()))
.collect_vec();
let books = b
.lines()
.map(|line| line.split(",").collect_vec())
.map(|line| line.split(",").flat_map(R::from_str).collect_vec())
.collect_vec();
(rules, books)
}
fn part2(input: &str) -> RiddleResult {
fn part2(input: &str) -> R {
let (rules, books) = parse(input);
books
.iter()
.filter(|book| !valid_book(book, &rules))
.map(|book| fix(book, &rules))
.map(|book| book[book.len() / 2].parse::<RiddleResult>().unwrap())
.map(|book| book[book.len() / 2])
.sum()
}
fn fix<'a>(book: &'a [&str], rules: &[(&str, &str)]) -> Vec<&'a str> {
fn fix(book: &[R], rules: &[(R, R)]) -> Vec<R> {
let mut b = book.iter().copied().collect_vec();
b.sort_unstable_by(|a, b| {
if rules.contains(&(a, b)) {
if rules.contains(&(*a, *b)) {
Ordering::Less
} else if rules.contains(&(b, a)) {
} else if rules.contains(&(*b, *a)) {
Ordering::Greater
} else {
Ordering::Equal
@@ -106,8 +108,8 @@ mod test {
#[test]
fn test1() {
assert!(valid_book(&vec!["97", "5", "13"], &vec![("97", "13")]));
assert!(!valid_book(&vec!["13", "5", "97"], &vec![("97", "13")]));
assert!(valid_book(&vec![97, 5, 13], &vec![(97, 13)]));
assert!(!valid_book(&vec![13, 5, 97], &vec![(97, 13)]));
assert_eq!(part1(TEST_INPUT), 143);
}