48 lines
1.4 KiB
Rust
48 lines
1.4 KiB
Rust
use std::{collections::HashSet, fs::read_to_string};
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use color_eyre::{eyre::*, Result};
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use itertools::Itertools;
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fn priority(item: &char) -> usize {
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('a'..='z')
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.position(|c| *item == c)
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.map(|i| i + 1)
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.or_else(|| ('A'..='Z').position(|c| *item == c).map(|i| i + 27))
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.unwrap_or(0)
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}
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fn initial(input: &str) -> (usize, usize) {
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let output1 = input
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.lines()
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.map(|line| {
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let (compartment1, compartment2) = line.split_at(line.len() / 2);
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let compartment1 = compartment1.chars().collect::<HashSet<_>>();
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let compartment2 = compartment2.chars().collect::<HashSet<_>>();
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compartment1
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.intersection(&compartment2)
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.map(priority)
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.sum::<usize>()
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})
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.sum();
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let output2 = input
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.lines()
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.chunks(3)
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.into_iter()
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.map(|group| {
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group
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.map(|line| line.chars().collect::<HashSet<_>>())
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.coalesce(|a, b| Ok(a.intersection(&b).copied().collect()))
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.map(|set| set.iter().map(priority).sum::<usize>())
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.sum::<usize>()
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})
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.sum();
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(output1, output2)
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}
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fn main() -> Result<()> {
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let input = read_to_string("input.txt").wrap_err("reading input.txt")?;
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let output = initial(&input);
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println!("output: {output:?}");
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Ok(())
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}
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