jonas.tngl.sh
Advent of Code solutions in Rust
feat: day 5 of AoC 2025
+142
-2
+140
aoc_2025/src/day05.rs
+140
aoc_2025/src/day05.rs
···
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use std::{collections::HashSet, ops::RangeInclusive};
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use anyhow::Context;
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use aoc_companion::prelude::*;
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use aoc_utils::range::RangeSet;
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use itertools::Itertools as _;
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pub(crate) struct Door {
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fresh_ranges: Vec<RangeInclusive<u64>>,
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available_ingredients: Vec<u64>,
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}
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impl<'input> Solution<'input> for Door {
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fn parse(input: &'input str) -> Result<Self> {
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let Some((fresh, available)) = input.split_once("\n\n") else {
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anyhow::bail!("missing empty line separating fresh ranges from ingredients");
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};
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Ok(Door {
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fresh_ranges: fresh
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.lines()
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.map(|r| -> Result<_> {
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let (from, to) = r
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.split_once('-')
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.with_context(|| anyhow::anyhow!("missing dash in ID range"))?;
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Ok(from.parse()?..=to.parse()?)
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})
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.try_collect()?,
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available_ingredients: available.lines().map(|i| i.parse()).try_collect()?,
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})
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}
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fn part1(&self) -> usize {
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fresh_ingredients(&self.available_ingredients, &self.fresh_ranges).count()
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}
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fn part2(&self) -> usize {
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disjoint_ranges(&self.fresh_ranges)
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.into_iter()
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.map(|r| r.count())
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.sum()
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}
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}
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fn fresh_ingredients<'a, I>(
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available_ingredients: impl IntoIterator<Item = &'a u64> + 'a,
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fresh_ranges: I,
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) -> impl Iterator<Item = u64> + 'a
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where
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I: IntoIterator<Item = &'a RangeInclusive<u64>> + 'a,
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I::IntoIter: Clone,
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{
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let fresh_ranges = fresh_ranges.into_iter();
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available_ingredients
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.into_iter()
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.cloned()
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.filter(move |i| fresh_ranges.clone().any(|r| r.contains(i)))
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}
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fn disjoint_ranges<'a>(
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ranges: impl IntoIterator<Item = &'a RangeInclusive<u64>>,
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) -> HashSet<RangeInclusive<u64>> {
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ranges.into_iter().fold(
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HashSet::<RangeInclusive<u64>>::new(),
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|mut disjoint_ranges, r| {
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let overlapping = disjoint_ranges.extract_if(|d| d.try_union(r).is_some());
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let union = overlapping
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.map(|o| o.try_union(r).unwrap())
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.reduce(|lhs, rhs| lhs.try_union(&rhs).unwrap())
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.unwrap_or(r.clone());
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disjoint_ranges.insert(union);
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disjoint_ranges
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},
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)
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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const EXAMPLE_INPUT: &str = "\
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3-5
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10-14
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16-20
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12-18
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1
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5
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11
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17
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32";
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const EXAMPLE_FRESH_RANGES: &[RangeInclusive<u64>] = &[3..=5, 10..=14, 16..=20, 12..=18];
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const EXAMPLE_AVAILABLE_INGREDIENTS: &[u64] = &[1, 5, 8, 11, 17, 32];
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#[test]
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fn parse_example_input() {
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let Door {
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fresh_ranges,
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available_ingredients,
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} = Door::parse(EXAMPLE_INPUT).unwrap();
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assert_eq!(fresh_ranges, EXAMPLE_FRESH_RANGES);
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assert_eq!(available_ingredients, EXAMPLE_AVAILABLE_INGREDIENTS);
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}
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#[test]
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fn example_fresh_ingredients() {
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itertools::equal(
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fresh_ingredients(EXAMPLE_AVAILABLE_INGREDIENTS, EXAMPLE_FRESH_RANGES),
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[5, 11, 17],
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);
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}
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#[test]
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fn disjoint_ranges_cover_same_ids() {
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assert_eq!(
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disjoint_ranges(EXAMPLE_FRESH_RANGES)
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.into_iter()
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.flatten()
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.collect::<HashSet<_>>(),
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EXAMPLE_FRESH_RANGES
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.iter()
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.cloned()
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.flatten()
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.collect::<HashSet<_>>()
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);
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}
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#[test]
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fn disjoint_ranges_are_mutually_disjoint() {
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assert_eq!(
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disjoint_ranges(EXAMPLE_FRESH_RANGES)
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.iter()
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.tuple_combinations()
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.find(|(lhs, rhs)| lhs.intersection(rhs).is_some()),
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None
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);
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}
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}
+2
-2
aoc_2025/src/main.rs
+2
-2
aoc_2025/src/main.rs
···
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mod day02;
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mod day03;
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mod day04;
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-
// mod day05;
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mod day05;
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// mod day06;
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// mod day07;
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// mod day08;
···
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door!(2025-12-02 ~> day02),
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door!(2025-12-03 ~> day03),
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door!(2025-12-04 ~> day04),
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-
// door!(2025-12-05 ~> day05),
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door!(2025-12-05 ~> day05),
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// door!(2025-12-06 ~> day06),
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// door!(2025-12-07 ~> day07),
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// door!(2025-12-08 ~> day08),