100 lines
2.1 KiB
Rust
100 lines
2.1 KiB
Rust
use std::collections::HashSet;
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use std::fmt::Write;
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const INPUT: &str = include_str!("../input/day06.txt");
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pub fn run() -> aoc::Result<String> {
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let mut res = String::with_capacity(128);
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writeln!(res, "part 1: {}", part1(INPUT)?)?;
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writeln!(res, "part 2: {}", part2(INPUT)?)?;
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Ok(res)
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}
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fn get_groups(input: &str) -> aoc::Result<Vec<Group>> {
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let mut groups = Vec::new();
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let mut answers = Vec::new();
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for line in input.lines() {
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if line.is_empty() {
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groups.push(Group {
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answers: answers.clone(),
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});
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answers.clear();
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} else {
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let person_answers = line.bytes().collect();
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answers.push(person_answers);
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}
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}
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if !answers.is_empty() {
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groups.push(Group { answers });
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}
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Ok(groups)
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}
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fn part1(input: &str) -> aoc::Result<usize> {
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let groups = get_groups(input)?;
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Ok(groups
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.iter()
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.map(|group| {
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group.answers.iter().fold(HashSet::new(), |set, answers| {
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set.union(answers).copied().collect()
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})
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})
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.map(|set| set.len())
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.sum())
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}
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fn part2(input: &str) -> aoc::Result<usize> {
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let groups = get_groups(input)?;
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Ok(groups
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.iter()
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.map(|group| {
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group
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.answers
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.iter()
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.skip(1)
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.fold(group.answers[0].clone(), |set, answers| {
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set.intersection(answers).copied().collect()
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})
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})
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.map(|set| set.len())
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.sum())
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}
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struct Group {
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answers: Vec<HashSet<u8>>,
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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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static PROVIDED: &'static str = include_str!("../input/day06_provided.txt");
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#[test]
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fn part1_provided() {
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assert_eq!(part1(PROVIDED).unwrap(), 11);
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}
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#[test]
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fn part1_real() {
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assert_eq!(part1(INPUT).unwrap(), 6382);
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}
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#[test]
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fn part2_provided() {
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assert_eq!(part2(PROVIDED).unwrap(), 6);
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}
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#[test]
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fn part2_real() {
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assert_eq!(part2(INPUT).unwrap(), 3197);
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}
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}
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