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2022 day3/rust: cleanup

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Xiretza 2022-12-03 06:29:32 +01:00
parent 5ad4f56771
commit c4268a0093
1 changed files with 36 additions and 22 deletions
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58
2022/day3/rust/src/main.rs
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@ -7,38 +7,52 @@ fn item_priority(item: char) -> u32 {
match item { match item {
'a'..='z' => item as u32 - 'a' as u32 + 1, 'a'..='z' => item as u32 - 'a' as u32 + 1,
'A'..='Z' => item as u32 - 'A' as u32 + 27, 'A'..='Z' => item as u32 - 'A' as u32 + 27,
_ => unreachable!(), _ => panic!("invalid item {item}"),
} }
} }
struct Rucksack {
left: HashSet<char>,
right: HashSet<char>,
}
fn main() { fn main() {
let mut data = String::new(); let mut data = String::new();
stdin().read_to_string(&mut data).unwrap(); stdin().read_to_string(&mut data).unwrap();
let mut sum = 0; let sacks: Vec<_> = data
for line in data.lines() { .lines()
let (left, right) = line.split_at(line.len() / 2); .map(|line| {
assert_eq!(left.len(), right.len()); let (left, right) = line.split_at(line.len() / 2);
assert_eq!(left.len(), right.len());
let left: HashSet<_> = left.chars().collect(); let left: HashSet<_> = left.chars().collect();
let right: HashSet<_> = right.chars().collect(); let right: HashSet<_> = right.chars().collect();
let common = *left.intersection(&right).next().unwrap(); Rucksack { left, right }
sum += item_priority(common); })
} .collect();
println!("{}", sum); let sum1: u32 = sacks
.iter()
.map(|sack| item_priority(*sack.left.intersection(&sack.right).next().unwrap()))
.sum();
let mut sum = 0; let sum2: u32 = sacks
for lines in data.lines().collect::<Vec<_>>().chunks(3) { .chunks(3)
let common = lines .into_iter()
.iter() .map(|sacks| {
.map(|line| line.chars().collect::<HashSet<_>>()) let common = sacks
.reduce(|l, r| &l & &r) .iter()
.unwrap(); .map(|sack| &sack.left | &sack.right)
assert_eq!(common.len(), 1); .reduce(|a, b| &a & &b)
.unwrap();
assert_eq!(common.len(), 1);
sum += item_priority(common.into_iter().next().unwrap()); item_priority(common.into_iter().next().unwrap())
} })
println!("{}", sum); .sum();
println!("{}", sum1);
println!("{}", sum2);
} }